You can also compensate for pronation by placing more stuff under the insole where you want to stop the foot from collapsing - under the "medial longitudinal arch", which most people just call "the arch", though of course the foot contains many support arches.
If you only need a little offset, go for it, lots and lots of people do it. But a big offset creates potential problems:
It may alter your spin balance. This may or may not matter.
It may cause your boot to gradually twist in shape, which looks weird make it hard to skate on one edge or another.
I am currently dealing with such warped boots - it was a real nuisance.