I feel your point regarding the WiFi devices and that they shouldn’t be recommended to casual users. But if you just set up an isolated VLAN with its own SSID and use e.g. homeassistant running locally to orchestrate them, then what’s the harm? If your goal is privacy, you need some kind of local “hub” anyway, and to me it makes way more sense to be able to place that machine anywhere, regardless of e.g. bluetooth reception to your smart home devices (since that is taken care of via the additional SSID on your WAPs).