TL;DR it's to help solve a math-based minigame that's hard
Sphere Break is a minigame inside of the video game Final Fantasy X-2. It's pretty fun. Most importantly, you need to beat it on super hard mode to get one of the best dress spheres in the game. It's got a lot of math stuff which, while it can be easy to do for some people, it can also be kind of annoying, espeially if you're freaking out about how far you are and there's a timer that's ticking down and you can't pause so it can be stressful. Anyway, that's where the solver comes in, cause why use your brain when a computer can do it for you?
The minigame gives you a core value each round (which is what you enter in the text field), and there's always a set number of "entry" coins (with the numbers 2, 3, 5, and 6). Then there's other "border" coins given to you randomly that you have to combine with an entry coin that, when added up, gives you a multiple of the core value. So like if it gives you "3" as your core, you can pick 2 as your entry and combine it with either 7, 4, or 1 (if any of them are there). What this program does is makes it easy for you to find what coin you have on the board and tells you what entry coin to pick, so you don't have to do simple addition and multiplication in your head, yay.
You really rack up points fast if you continue to keep the same number of coins to get a sphere break (so like round 1 you use two coins, round 2 you use two, etc); that's called a "coin count echo". You can also get more points by using a multiplier echo. You get more options the higher up you go, and that's really what this tool is useful for, so go ahead and set 4 for your echo target and 4 for your multiplier and see how it works for you!
Other projects are here.