There is a blade size and skater weight limit CYA disclaimer and many of the testimonials talk about using these with the younger age-group players.
I would expect the axels to break before they wore through the rubber. Since they only show hockey heel loops, I'd say the fit is pretty secure for those skates. I have hockey guards for my figure skates (that's what happens when you buy by color without looking at the package) and they slip off regularly.
I do like the idea of using these to break in skates off-ice instead of marching around the house on them. However, with the height of the wheels added, it would be like skating on platforms or stilts.
Definitely no stair climbing.