Saw something about this a few months ago with the head of the EU bitching and moaning that there is no need for it and they the entire EU should be unified on the exact same time "to make trade easier" (Cause no company in the world has any idea how to trade with a country in a different timezone, apparently).
People wonder why the UK voted to leave, and countries like Italy are on the edge...it's for stupidity like this. They want to do stuff simply for the hell of it, with no actual thought process involved lol. Clocks going back/forwards is something everybody is fully used to. It happens twice a year, and for the majority of us...has done for our entire lives...
That is the comment of an uninformed someone who hasn't done automated transactions with countries in different time-zones. For those that do/did, they are fully aware of the headaches caused by time-zones.
An example: not sure if you are aware or not, but it is no secret that European countries have their energy grids interconnected. And that energy is distributed between countries at the exact moment that is needed. In an ideal world the energy grid contains as much energy as its demand. And this has to happen according to JIT (Just In Time) principle.
Communication between energy producing companies, energy distribution companies, energy selling companies and companies responsible for maintaining the grids the energy travels on is therefore essential. In a lot of countries, energy is handled by one company and that gives consumers the (very) false impression that it is simple. It is not, I can assure you. Not on a regional level, not on national level and most definitely not on international level.
In Europe it is so that European consumers are allowed to buy their energy from any provider in Europe. Because that concept results in the most honest energy market where energy companies mostly compete on price, but also in uptime and secondary services. All to the benefit of every European consumer. Concepts like that are a good thing in the long run.
Unfortunately, energy comes in different forms. Natural gas is the most problematic one. In the Netherlands it is so that you need to pay your energy bills on a monthly basis. But each year energy companies review the consumption of energy and sometimes that results in the consumer having to pay extra, and sometimes the consumer gets money back. The consumer must pay for industry agreed upon caloric value for each cubic meter of gas they burn. Sometimes more amounts of cubic meters of gas are required to have the same burn, sometimes less. The caloric value of gas is never constant because of a lot of different external influences (temperature, quality and humidity are the main ones). And those differences will be reviewed/recalculated on a yearly basis.
Lots of European countries must import their gas from Russia, which means that gas must travel to quite some countries and time-zones before it arrives at consumers. Gas distribution companies and grid companies therefore need to be finely attuned to each other on a international level. Supply and demand is therefore always in a "fluid" state, but still must match the supply==demand rule for the grid itself. Automatization of international systems is therefore essential and you'll need proper communication about the correct amounts of energy arriving at the intended locations on time.
All that text above only describes a small part of the energy market in Europe, but there are much more and very different markets which would also benefit greatly from the lack of time-zones.
Unfortunately, there is more that makes time-zones a royal pain in the behind. Some countries want to apply their time-zone "perfectly", which results in time-zone differences that are not an hour, but only one or more parts of an hour.
And then there is still the difference between the moments when a country applies the DST change. In Europe it is common that countries use the seasonal changes to apply DST changes. The United States, for example, uses the equinoxes to apply DST. On average there are 3 weeks between an equinox and a seasonal change. So in that intermediate 3 week period time-zones are a really big mess and an absolute headache for internationally operating companies. Add to all this time-zone misery the fact that not all countries use the same calendar and the clusterf.ck that is time-zones is finally complete.
Another example: here in Paraguay it is the president who decides the days to apply the DST changes. If he/she would decide that today a DST change and tomorrow the other DST change must be applied, than it will happen that way. Now it is not as extreme like that, but Paraguay is not the only country that does this. Still, this random selection means that for about 2 months in the whole year I cannot use any internet time server for keeping my computers in sync. Let alone doing any automated time-based tasks that require me to connect to any country outside Paraguay.
With that kind of randomness, you might as well not use DST at all. But sure, for those that live and work in one and the same time-zone, they bitch and moan about getting rid of time-zones, because its just a small adjustment in your alarm-clock/microwave/oven etc. Those that have to work around the true implications of the clusterf.ck that is time-zones know better.