IKB

I think it is because of the angle that light passing through the lens hits the Sensor. Light passing through the centre of the lens hits the centre of the Sensor directly so the full value is...

I use an X-T1 and I can't see any reason to move on, I'd rather spend money investing in lenses.

It's marketing to an easily impressed, non-technically aware audience. You see it everywhere, my new Samsung washer/dryer is marketed as having a 'digital inverter motor' as if it were something ...

The big deal was that you could buy it from Poundland shops for - guess what?

A pound a roll.