Good on them!
Allocated seating should stop most of the rush that you get at the departure gates. When i flew with EZY, about a week ago from AGP, most passengers didn't seem to understand that Speedy-Boarding passengers only actually does mean Speedy-Boarding passengers only and not boarding group A, B, etc....
Allocated seating gives families, those who need additional assistance & spotters the reassurance of the seat that they want.