Two things:

First: Custom classes, such as custom grid classes that depend on having custom column classes (which must be defined in a prg) would be able to load their PRG based classes without the developer having to set them up.

Second: When you develop a custom control that contains other controls these controls would be displayed correctly at design time.

In my opinion, not having design surface control over your VFP developed controls makes the user experience feel unprofessional.

Like I said though, that's just me...

Thanks,

Steve