This is sort of my argument against crackle/shatter.  Take this lovely heart-stopper for instance — OPI Tasmanian Devil Made Me Do It:

Which is GORGEOUS GORGEOUS GORGEOUS.  Just a total wow color.  So I went over it with some OPI Silver Shatter, expecting a similar cover to the OPI black shatter I did on some other nails, but the end result was wayyyyyy less cracked and sooooooo much more silver-dense than I had hoped for, so kinda boo on that.  I want to appreciate the silver shatter, I really do, but it covered up way too much of the Tasmanian Devil and that’s a bummer.