Let’s say for example you wanted to use a Thor in a raid. For the sake of simplicity, your current boost strat is 10/0/20, but this is too fast for most raids. What if since you already have 30 boosts invested in Thor you could redistribute the 30 among all 3 categories to a different configuration that you could use for raids. Then you could do a 10/15/5 configuration that might be more raid compatible. Then this wouldn’t prohibit you from using certain guys in either arena or raids.
Disclaimer: I have no idea if the mentioned boost layouts are actually a thing. I just used some easy numbers.