zenox98 Sure! There are a few reasons why this would be useful.
1 - If this was done via the animation system, you would have to create additional frames for each possible state. Say that you had a platformer and you wanted to have this sort of system where you flash white after being hit (similar systems occur in lots of games). You would need to make white jumping frames, white running frames, white attacking frames, etc etc. If it's possible to do something programatically and not put additional strain on your art team, it should be done.
2 - This is an effect that lots of games make use of. The most popular is how enemies in shooter games turn red when they're low on HP - if masking was a feature, we could implement that in 30 seconds with no additional art required.
3 - You can easily create visual variation with a system like this. For example, one piece of Dragon art can be a Red/Black/Green/White/any other color dragon, without having to export a new set of art for each color.
There are seriously a ton of uses for a feature like this. IMO, we should hand off as many tasks as we can to the computer. Imagine if we didn't have an opacity control, and had to draw all of our frames in varying levels of transparency if we wanted that effect. It would add so much work!