We still have a problem if we can't make a distinction between the different continuities and we have to waste time trying to distinguish one version of an Earth from another.
Even though Hypertime manufactured a mechanism for changing continuity on one Earth, Mark Waid still gave us the concept of the Kingdoms and we were shown that there's a great big Multiverse out there filled with possibilities.
We still have to have a way of dividing up those possible Earths that doesn't leave us feeling very confused. I liked Hypertime but I think the reason it failed to take off was because it's too difficult. My visual metaphor for Hypertime is steel wool--that's what it looks like to me. If you could pull the strands of steel wool apart and straignten them, then you'd see clear lines, but they're all bundled together and it's hard to tell one strand fom the other.