Reading their alternatives, it strikes me with "ZCTA's are the worst form of small area aggregation except for all others."
Its not a great geography to use but it is quite useful if you know it's limitations and inaccuracies when you get into it. Stuff like multipolygon entities, island-polys, etc aren't fun to resolve but can be accounted for.
Add on that ZCTA's will historically follow some sort of actual boundary(rivers/highways/etc) they can tell a story in a way Census tracts can't.