Indeed, most of the regular nuclear was can still be used as fissile material, if someone bothered to reprocess it. It also contans a lot of various useful (even valuable) elements, created by permutation during fission.

The amount of realy useless & dangerous is very small. Separating it from the rest is the issue, both economical & political.

Still seems like a better option to solve than trying to find a mythical ideal permanent storage place.