Very much so on the matter of clear communication, because while it might not always be easy to know when or how to use the subjunctive mood, readers understand it when they see it. It’s built into English, and it’s an important part of the living language — even for people who can’t explain it technically.

Maybe it’s a little analogous to brush work in painting. Plenty of us amateur appreciators of art can’t explain why particular types of brush strokes matter. But they do matter, shaping our appreciation of a painting even if we don’t know how.