I was sketched out by their move to get rid of inactive free accounts, but this is nice to see. Really hate the idea that if I'm unplugged just for a bit I lose a ton of contacts.
You need to be unplugged for 12 consecutive months for Proton to delete your account because of inactivity though, which seems fair for free tier accounts. A simple login is enough to prevent this, you do not need to send an email or whatever, simply log in once a year. You also get reminders sent to your recovery email before this happens. Data storage for inactive free tier accounts isn't free for Proton.