“You _will_ lose them”, as in, somehow Immich will do something to lose them (like making a mistake in a dedupe process which deletes the wrong things), or are you just saying you also need to keep backups?

Whatever system it is on will die, etc.

unlike Photos, you don’t have a team of professionals managing it 24/7.

(that said, takeout your Google Photos too, because single point of failure, etc).

More so that any storage system will eventually fail me thinks.