I've also been doing that for ~10 years. It's not the easiest service to run, but it's definitely not the one I had the most issues with. I would agree that in the professional field, there isn't much advantage to host it yourself, and I would advise going with hosted services in this case. But on a selfthosted community forum I see no reason to say such things to a new user trying it out, especially if they don't plan to host other people mailboxes.

I'd say the difficulty depends mostly on the stack you decide to run. I've tried Microsoft Exchange, which is very complex, postfix which is okay once you get the hang of the config file syntax, and opensmtpd which is delightful to configure given its simplicity. Docker also helps tremendously compared to what was available 15 years ago.

Actually delivering emails into inbox is another difficult aspect, but now there are just so many good resources to learn from that you can easily figure out what to do.