This is really a bad thing since i can only use YGE Telemetry with the EX Bus and not with the Ext. channel input. This means, i have to give up one servo channel for EX Bus. And this means i have to use a 10 channel receiver if i need 7 servo channels.
i guess this is the wrong addressee for your claim: Jeti cannot force YGE to implement EXT too. i would ask YGE.... even i do not think they plan to implement the older protocol too.
btw: ... your are not really buying a 7 channel or 10 channel receiver with Jeti. it's more a 7 connector or 10 connector receiver... all the Rex receivers do receive "all" channels and can map any of them to any servo connector - or "all" (8/12/16) together to digital single line like i.e. S.BUS, UDI, PPM, etc
If Jeti would enable the option to switch the EXT port to EX Bus, there would be a way to lock out yourself from the RX. As it is now, you always have the solution to connect with a JetiBox to the device and do e.g. a Factory reset. Not too bad.
There might be some point in time where Jeti should switch to a new and leaner protocol, and then to introduce a new device access box.
But as it is today, it makes sense to keep the EXT port as a JetiBox compatible port.
The REX receivers can be reset to factory via "Geräteübersicht" and underlying EX Bus protocol. For this process Ext. is not required from my point of view. However, i agree, it needs to be consistent if Ext port can also be configured as EX Bus.