So how is the company making profit from this, is it ad based?
If I were a Business guy, it's like viral advertising. Companies developing software should have a couple of bucks in the bank, not trying to monetize every last click from Day 3. This is gonna sound harsh but "donating 3,500 pounds" is peanuts for a company, it's like 6 weeks of fast food job pay. What they gain instead is a "use case" for 10 cents a piece where ordinary ad campaigns might run them thousands of dollars for a particular ad campaign in the old style.
In the download process they ask for Name (of course I am "User"), Country, and an email address where they can "From time to time, we will send you our newsletter that keeps you up-to-date on what's happening at SoftMaker. This newsletter is free of charge, and you may unsubscribe at any time.". So it's that age old "Free As In Beer" by trading a newsletter recipient for a one time 10 penny donation. Standard business tradeoff.
Edit2: Now when you run it, it wants a name, email address, and serial number. On a second screen it tries to ask for your address and phone number and more. You can bypass that. Then for every startup it seems to show an ugly "sidebar" that I can't figure out how to permanently turn off. It's basically an ad for itself. Summary - more typical tricks behind the "yay free" hype that starts threads. I'm going back to LibreOffice.