I used VirtualBox on Linux to host my Home Assistant server for a while. I kept having odd issues with usb devices. I’d have to disconnect and reconnect them to get them working again.
Many people in the HA help groups say not to use VirtualBox, and at first I thought they were basing that on old info. But then I started having issues, too. On the other hand, kvm has been rock solid for a long time.
So I’m glad to see they continue to develop it, but I wouldn’t recommend it for heavy duty use. It’s useful to dipping toes into virtualization, or maybe for running systems for the short term (a few hours here and there, or something), but for long term use, I’d go another route. It’s certainly easier to set up the network in VirtualBox, I’ll grant that - it took me a while to get it right for HA on kvm. (Of course, that’s a one-time setup thing, too - I shouldn’t have to touch it again. And don’t ask me what I did, because I don’t remember!)
I use a helper for some entities. For example, the temperature sensors that come in via rtl_433 that rename every time I put new batteries in, or my phone or my wife’s phone. That way I only have to change the helper, in one place, versus having to change it in countless scripts, scenes, buttons, etc.