Lol, I agree with you, but to be fair I learned about VPD and the benefits of controlled RH in Botany class when I was in college studying for greenhouse production practices. It's not so much that it's necessary, but it can be beneficial.
We were taught that there are benefits to manipulating RH, but you can also manipulate other variables to make it work if you can't control RH. For example if RH is really low like <30% in a warm environment, reducing calcium in the feed slightly and running a reduced ec can help keep things trucking along.
That said it was generally accepted that optimized VPD has better production values. Whether it's worth it to chase down the marginal improvement in production at a small scale like we grow at, is really where the question lies. Probably not. But some of us growers can get rather obsessive trying to grow things the best we can, and practicality is often overlooked. I see it as a similar situation to Co2 enrichment. Does a plant produce better at 1200ppm? Yep, but does a plant still produce dank nugs at 400ppm? Yep.