Doesn't that mean you can't use your phone, unless you disconnect your router? Or are you using a very long USB cable?
I have no experience yet with the USB-tether option.
The WiFi hotspot functions well. What happens during phoning (which doesn't really happen often these days), depends (apparently) on the provider.
I use a dual-SIM phone (ASUS Zenphone 4 Max); when my Dutch SIM is active for data, I can phone without any problem (internet connection remains active, so all users connected to my router don't even notice I'm phoning).
When my French SIM is being used for the internetconnection, the hotspot remains active during phoning (so the connection with the wireless bridge remains in tact), but has no data (no internet connection for connected devices).
No, I understand that is the current setup: Wifi hotspot on the phone, and a wireless bridge on the WAN side of the router to link to the phone.
Correct: phone has WiFi-hotspot connected to wireless bridge; bridge feeds wired WAN to router; all devices connect to router (WiFi or LAN).
So for my home network the situation is (almost) the same as when I used ADSL.
When en-route all devices I have on board (other phones, tablets, laptops, E2-boxes) connect directly to the hotspot.
Of course the latter situation could be used at home as well (although I'm not sure if there's a limit to the number of devices a phone can serve), but I prefer to have a 'normal' network setup.