AFAIK, mesh is only useful for expanding the WiFi footprint, not to accommodate more connections. And if you need to use satellite repeaters with it, the network will be slower. Most IoT devices operate intermittently, using very little bandwidth. Be sure and do your homework before investing in extra AP’s and make sure they are easily returned if found to not be helpful.
-Al-
Understood. Possibly mesh routers can handle more connections because the hardware is more robust than the hardware in routers that are a little long of tooth like the Airport Extreme. Additionally, I gather that mesh routers are more adept at tracking cell phone and iPad users as they move about. It will be a while before I need to upgrade, so I have time to learn from other’s experiences. For example, The Wirecutter recommends the Netgear Orbi mesh router, but some people were less than pleased when an automatic update caused a bunch of issues. It will be interesting to see which horse in this race can avoid big missteps.