But in that case you don't want more than a white board. There are many cases, especially in the corporate world, where you want a single-purpose device that isn't going to need maintenance, group policies, etc etc.
One of the best ideas I ever had was getting a completely separate network connection for our guest WiFi. It was trivial to implement, keeps our diagrams and GRC needs simple, and we no longer have to worry when a PHB wants an IOT lightbulb that'll no doubt get hacked in 24 months.
Damn I wish our company would stop buying Alexa/Home/Chromecast/Sonos/IoT-box-from-down-the-street.