Zwift Companion App - same WiFi?

Why does the Zwift Companion App need to be on the same WiFi Network? It makes things unnecessarily complicated. Would be enough if the Companion-Phone is online?!
I have to provide a Hotspot from my iPhone to my MacBook and so I can’t use ZC anymore.
Pretty sad!

It actually doesn’t have to be on the same network. The Companion app device just has to be able to see the game app device on the network. On a lot of setups this does equate to having to be on the same wifi, but that isn’t an actual requirement. It depends on your router and how it is setup. Some mesh networks can be problematic.

Well, this doesn’t seem to be relevant to my question. Do I miss something?