I don’t get why these bridges are sold/seen as a way to (primarily) control RF devices from the IP network, rather than the other way around,

i.e. Given that RF transmitting switches/fobs etc are so incredibly cheap, and the batteries last forever, a way to bridge RF switch/button pushes (from any 433MHz tx) into Google Home or proper HA commands would allow wall switches and portable remotes anywhere and everywhere they might be useful.

I thought that’s what I was going to get with my Sonoff bridge, but unfortunately it wants to receive instructions from Google Home, not provide them to Google. Alexa, Philips, or anything else as far as I can make out.