1. Easier installation.
2. Mint configuration of desktop settings
3. Mint tools (Warpinator, Hypnotix)

But where to get the AppImages from? Who’s maintaining? How to do Security Vulnerality Tracking for them?

Don’t panic!

I don’t get your point. Why should somebody do this every day?

As the experience from other users in this thread, it seems not extremely rare to have an overgrown ~/.cache/ folder. So checking it from time to time is a good advice. If we all do this for a time, and create bug tickets for software which is not cleaning up. Then this problem will hopefully go away with future software releases.

Because some users experienced accidential grows like OP had 160 Gbyte. So general advice for linux users can be stated as: Check your ~/.cache every now and then

Critical systems/servers shall better be monitored as you suggest.

not necessarily during runtime

So OP’s headline should be saying instead: Reminder to CHECK your ~/.cache folder every now and then

I always felt that there should be some user directory like /tmp/ which will be wiped regularly.

Is it safe to clear ~/.cache/mozilla/ while Firefox is running?

That doesn’t help outside of home. When we are in an untrusted network then the DNS mess makes us vulnerable for spoofing attacks.