I've found that a yoga block is actually a useful tool for improving balance and strength if you're (like myself)
Let's say I'm working on my mohawks. I lay the cork block wide side down, step on it with one foot, and then I do what I'll call the 'mohawk approach'. That is, I keep the 'skating foot' on the block, tuck the free foot, stroke, bring the free foot forward to the middle of the skating foot as in a mohawk. I don't switch feet, this is just my 'approach' to the turn.
While standing on the block I focus on balancing on the correct edge and holding that edge, on the right spot of where the blade ought to be, and holding the correct arm and body position. I've found that the couple of inches of elevation really, really amplifies every bobble of every error.
After a few days of experience with the cork block, I switched to the foam block. The foam block is just a bit squishy. If I'm careless and let my weight get too far back, the block squishes down, reminding me to keep my weight more to the center of my foot.
Once I mastered that, I moved up just a little bit and started doing my mohawk approaches on a balance disc which is much, much, much harder. I originally started on the balance disc, but it was frustrating. Working my way up by stepping through the cork and foam blocks, allowed me to build my balance and strength without having to worry as much as if I'd started on a balance disc.
I feel it helped me get comfortable with all the tiny skills necessary to get my free foot to the center of the skating foot and work on my mohawks proactively off-ice.
And it was cheap, just using some handy things I had around the house.