Plenty of people travel 'initially in the wrong direction' on routes such as MAN-AMS-USA, so if the price is right, no reason why SEN-MAN-USA/DXB etc couldn't be attractive to someone?
Yes, not going to be huge in numbers, but MAN is starting to pick up as an alternative transit point. Had over 180 pax off a TCX LAS-MAN connecting onto various Flybe flights last week alone.