They’re more optimised for metro routes because of better acceleration, 2+2 seating throughout the whole train and they can more easily form 10 car units
Wouldn't 2+2 be more optimised for longer-distance journeys because they provide the maximum comfort and high-density seating is less important?
That was always the way in BR days, the 2+2 CIGs were used on longer-distance/fast services while the 3+2 VEPs were used on slower/shorter distance/peak services.