I play my 3DS while waiting for my bus before school, on my bus too school, while I wait for school to start(my stupid bus just has to arrive an entire hour early), at lunch during school, while I wait for my bus after school, and as I ride my bus home after school. So yeah, my 3DS gets a lot of use outside of my house.
I guess it just depends on who you are and what your schedule is. But to some people, portability is very important.
But of I course, I never did have problems with my XL.