It's not about doing 70's style kung fu zip-zooms, it's about following focus. Cinema lenses have longer focus throw than stills photography lenses, typically.
If you don't have a single focus or focus through system you're cutting yourself off from being able to do all kinds of shots with moving talent. It's like having to write a paper and being told you can't use adverbs or pronouns or any word with more than three syllables. It's doable but it's far from ideal, especially when you have a choice.
Actors will be able to move only within the plane of focus. Or not move. Forget about dolly or tracking shots that also aren't also very restrictive. Prepare to eat a lot of blown takes. Less experienced actors tend to over-animate, because they're not acutely aware of how small moves can be read quite well on camera, or they don't hit their marks. A good 1st AC can save what would otherwise be a lost take by being able to judge how far off the mark talent is and adjust focus accordingly.
It's not a matter of obsession, it's one of necessity for certain kinds of content. I really could care less what someone did in their short film or music video to somehow "prove" that this wasn't necessary. No follow focus isn't a "dogma" that I can get behind and would sooner just shoot spherical. Dual focus and anamorphics that force you to use telephoto lenses work great for demos and test videos though.