I think using proton service is more for privacy. Nothing is free anyway. If you use Google or anything else that's free, you are paying them with your data, and proton they don't make money from ads, nor do they have them and those servers won't pay itself, but yea their ecosystem is pretty good, I mainly use email and VPN but there is a service called SimpleLogin that basically makes alias for your email, which you can send and receive from, and I believe proton own them now (dont have to pay for it), I basically use that with browser extension that generates random email each time, and we can deactivate the email so no need to bother with unsubscribing from promotional email and all.