Fortunately, SFA3, another 2D Fighting Game by Capcom, has been implemented into the Lua script that runs in FBA-RR and Mame-RR for displaying hitboxes.
There's also a chance that Jojo's, yet another 2D Fighting Game by Capcom, might also be implemented.
For me it's amazing to see the inner-workings of these games that people have played for years and years. The major intricacies of footsies becoming actually visible right before you.
It's shocking and exciting because the visual sprites don't always match up with the game's hitboxes. A great example is what we see in the thumbnail on this blog; Lilith MK has her leg no where near the actual hitbox. The real hitbox that interacts with the opponent is drastically lower than her sprite's leg appears. Just glancing at the image to the right, you can very clearly see that the attack-box (red) is quite a bit lower than Lilith's extended leg. Imagine for a moment that you can not see her hitbox and only her sprite (like normal gameplay) for round one, but the second round you could only see her hitboxes and not her sprite. I'm certain it would put things in perspective.
While many players can learn the game through trial and error, actually seeing what is really going on can drastically change the way we think, and therefor play.
Personally I always get blown away by how cross-ups appear in-game with hitboxes overlayed onto the sprites. It also gets me giddy to see basic anti-airs used at a pixel's distance.