I need storage to work, and I don't have enough time to get into ZFS's guts unless I'm going to do a video or longer blog post on a specific topic.
TrueNAS gives sane defaults, exposes most of the basic features through a (relatively sane) UI, and... works.
I still use ADM on my older spinning disk NASes, though—RAID 10 just works, and is fast enough for what I need, and the fact I have three copies of everything (one 'offline' (ish) on Glacier Deep Archive) means if I do ever encounter a corrupted file, I can grab a copy from one of the other backups on different media.
If you're a storage nerd / data hoarder, then it's common to spend more time and go deeper than what something like TrueNAS or some other UI gives you. Otherwise it's like the McDonald's of storage software.