Originally Posted by CPH-Flyer

Oh wow you had the app for two decades, that is more than the rest of us.

But seriously, for TXL it is not so much about the check in, it is about the actual physical flow of the airport. And it is a stretch to get the bus in go through security, and get the bus back out again. If the plane is parked by the terminal and boarding is only walking it might be fine, but not certainties