I think Home Assistant is when you want to connect multiple IoT devices together and have automations around them, that you normally can't do because the devices are using different protocols because they're from different manufacturers.
But if you don't need that it's probably a useless overcomplexification.
I use mine so I own my own data. Almost nothing I use talks to the internet but I still have a smart house (that runs just fine when my internet is out).
And while it took some tinkering to setup (back in the "edit all the yaml" days), I barely touch it anymore, I have it set how I like it and that's that.
But if you don't need that it's probably a useless overcomplexification.