ARM processors can be as complicated or as simple as you want them to make. x86/x64 Processors are complicated, period. You can see ARM architecture as a specialist, while the x86/x64 architecture is more of a generalist.
For both there is a big playing field. However, in data-centers with lots of customers that pay for computing time/resources, it is handy to have the right amount of servers active at any given moment. Energy and cooling costs are quite high. So if a server in a rack can easily be turned on/off/standby with the varying demands, that helps a lot. Doing this with x86/x64 is harder than with ARM. Practically all brands/models of smartphones come with ARM, not x86/x64, because of this.
The ARM-based DPU mentioned in the video are now so fast and powerful, that these can host a hypervisor (a requirement for virtual machines) on itself, making it even easier to activate/de-activate servers as needed at any given moment. Apparently there are already DPUs with 200Gbit/sec network transfer speeds (200 times faster than the average home network). That makes it viable as network storage. Couple that with nVME drives and you will hardly notice a difference between local and network storage anymore.
Network storage boxes can be simpler (not necessarily cheaper) and very fast with an ARM chip that is designed for that particular purpose. A generalist CPU that could match the ARM chip would be expensive to purchase and run.
Linux is already available for the ARM architecture and even Microsoft is busy with preparing Windows to run on ARM (WinRT was their most recent (failed) attempt) and Apple will finish the transition to the ARM architecture (all their hardware and software) within 2 years. That is their plan anyway. Generalist chips are nice for desktops that have many different use-cases. But with everything moving to "the Cloud", specialist hardware in data-centers (and much simpler hardware with the customer) is far more efficient. If only for the reduction in energy-consumption alone.
As I understood it, all currently available renewable energy sources on this planet do not produce enough energy (over a 24-hour period) to keep the internet and all it's data-centers on this planet running (over a 24-hour period). Not that renewable energy sources produce a little amount of energy, the internet as a whole and it's data-centers consume much more energy than you expect. Streaming video is very costly factor. Not directly in the electricity bill of a consumer, but the hardware needed to keep up with customers 1080p/4k/8k video demands 24 hours a day needs lots of energy.
Whatever can be gained in energy efficiency counts for a lot. And yes, producing a movie DVD (including case, booklet, print, transport to different continent etc.) is cheaper energy wise, than having it online available 24-hours a day. How wrong or illogical it may sound, the convenience granted by the current internet infrastructure is far more problematic than most people realize.