Well there are a lot of characters you can't throw fireballs vs as a regular shoto like ryu. Nash/bison in particular are annoying because you're just feeding them trigger/resources. Having a fireball that travels less than full screen allows you to control space they might dash/slide/scythe into without allowing them to sit back and absorb freely. It also opens up a mixup of is that fireball I just threw one you should neutral jump? Absorb? Etc.
Also the fireball explosion when it ends is useful for stopping people from low profiling your fireballs. Characters that have moves that put them under projectiles can still get hit by the burst. So characters like Karin, ibuki, Mika, etc need to be careful sliding under them at certain ranges.