I wouldn't get wrapped around the axle regarding pedestal weight, they are designed to be bolted to the floor for smooth and safe operation..
you might get away with sharpening a small chisel but any substantial metal grinding or shaping you'll be dancing around the shop if it's not bolted down..
heavier ones like the 150# stand will give you more stability but it will still move and even push over unless bolted down, hence the floor mounting holes..
best practice is to get yourself a stand stout enough to support the weight and horsepower (grinding feed force) of the grinder you're operating and bolt it down for worry free operation..
it's similar to cutting or grinding metal parts without a vice, if it's scooting around it's very difficult to apply any usable force on your work piece as well as dangerous..
advice from someone that has supervised a dozen repair shops across 30 years
good luck!