If you want to do anything more than just run Home Assistant with the system it's on, I recommend ditching their whole OS and Supervisor, and just running HA Core in a virtualenv.
The developers have shown that they're very opinionated about how their software should be used, and they're hostile to everything that falls outside of that. That makes their OS totally unusable as a general-purpose solution. Besides, it's an OS that doesn't get regular security updates, so that alone should disqualify it from serious use.
Well their approach allows them to deliver software that works without being inundated by issues related to someone’s peculiar set up. I don’t think ‘hostile’ is a very fair assessment.
I totally understand that they don't want to support peculiar setups, and I get why non-standard setups are labeled as unsupported. But actively asking for your software to not be packaged, even under another name, and threatening to change the license to prevent that [0], is a whole other ballgame, and I do consider that hostile. Hopefully this was just an extreme outlier, but the desire to not have people use it in ways the developers don't like, even if they aren't being bothered with it, seeps through in a lot of their work.
Of course it's their right to steer their project and decide what you can and cannot do with their software, but it does make Home Assistant significantly less attractive for lots of people that don't agree with all their choices (and judging by the mixed feedback in this thread, that's not a negligible group).
FWIW, I am in the same camp as you. They seem oddly hostile to FOSS development (as shown in your comment and the top comment you replied to), and as such, I hesitate to use it for that reason.
+1 to that - HASS is nice option if you don't want to host anything else on this device and/or really want add-ons and in-gui upgrades.
For me it was giving up too much control over the device. I'm running plain docker image for over a year now with zero issues. Upgrade is done by simple bash script, functionality offered by add-ons can be achieved by manual installation as add-ons are simply wrappers for various software.
The developers have shown that they're very opinionated about how their software should be used, and they're hostile to everything that falls outside of that. That makes their OS totally unusable as a general-purpose solution. Besides, it's an OS that doesn't get regular security updates, so that alone should disqualify it from serious use.