To give the GBA it's dues, it's pretty damn impressive what can be achieved on a GBA. It's a mature platform with a lot of freely available (unofficial) dev-tools and no operating system to get between the coder and the hardware.
I can even sort of see his argument, because I'd have liked to own a GP32 years ago, but there was no way I could justify it: No commercial releases and I already owned a GBA with a flash card.
On the hardware's own merit, there's NO denying that the 2X and 32 blow the GBA right out of the water, though.