Depends on what you do with it. In accountancy we and most of our clients work with Microsoft Office desktop. Also things like templates based on CRM work better with actual Word.

Edit: Libreoffice is also a bit annoying since the settings aren’t in the same layout so helping others becomes harder. Not sure if they implemented it since I am not that well versed with it as with Excel, but I belief they don’t have a PowerQuery alternative?

Does the dualboot of Mint cause any issues for Windows? I only tested it very briefly on somebody elses machines where I needed to wipe windows and install Linux

It’s not “his” company, the company is owned by the Proton foundation (of whatever it’s exactly called)

Yeah Yen is an idiot, but his power is more limited than with a normal CEO company structure and the Swiss law is a lot stricter than the competitors law in like Germany.

Just like with any of these mail servers, buy your own domain just incase the company switches gears and starts selling your data or whatnot