Keep in mind that Home Assistant provides ready-made images that behave like an appliance and can auto-update. In fact, it doesn't even give you a shell/SSH by default and such access is discouraged.

Thus the Linux/RaspberryPi underlying complexity is irrelevant to the user - the "complexity" is to dd/BalenaEtcher/etc a downloaded file to an SD card, put the card in the Pi and connect it to power. From there it's available over the network and can be configured through a web browser.