I’ve found when doing early levelling tests for Normal that it’s surprisingly good to max before the Bonespike for Ravenous Earth becomes available and only for a short while, everything up to pre Darius maybe? It’s in a similar boat to Devouring Swarm or Night’s Chill where it mops up trash enemies. Often in Spectral Wrath’s case, you can get hit once while running towards a crowd, trigger the debuff on all of them and they’ll slowly die as you’re running towards the next crowd.
For Elite/Ultimate starts though? It’s nowhere near strong enough on it’s own to clear crowds but the passive RR is still appreciated for your stronger spells.