The other thing that my “Lite” install (which doesn’t include Straightforward direct-delivery incoming mail does is Handling bouncing e-mails as well as enable automatic upgrades (and automatic reboots when those upgrades require them).
A few times a year, a command line rebuild is required to update the base container. And every couple years a more complicated upgrade like PostgreSQL 12 update happens, which though well documented, can be a bit hairy for someone unfamiliar with the command line. But as I said, I don’t recommend it, but I’ve seen people go years doing nothing whatsoever!