Y'know, I'm surprised you don't see sports bras more often in comics(though they sure show up in mine), even from a totally sexist angle(this is Mr. Smut Comics artist talking now): they keep the breasts firmly in place so you can draw them the same panel to panel, they keep them tight and high and round against the chest, what exactly is not to like from the artist's OR fanboy's POV? It actually does what they want better.
No chest doesn't look good in one. Period. And yet they're also practical and women, like, actually wear them in real life and stuff.