Funny that ... I've only been developing instrument approaches for about 15 years and have always seen a need to have a start point at an Initial Approach Fix/Waypoint. This is because the approach is predicated on a specific maximum IAS, so we need to make sure the pilot has slowed down the aircraft as necessary, before passing the IAF/IAWP.
I think some companies might be playing games to suggest that the approach only starts at the FAF/FAP/FAWP. Certainly, that's when the approach gets really serious, complete with further speed reduction, reduced terrain clearance, etc., but in most countries that I'm aware of, clearance for an approach is given before passing the IAF/IAWP.
That said, I know there are instances where ATC will vector an aircraft onto the approach just prior to the FAF/FAP/FAWP. But this is simply a convenience issue and won't apply at every airport for every type of approach.