Funny no one has mentioned the main reason remote tire filling is recommended. It's called a Zipper Failure. Split rims are a thing of the past but zipper failures are a real concern. Especially with RV tires as they are often abused by letting them sit in one spot for months at a time. Then run at freeway speeds for a couple thousand miles. What happens is that the steel belts can rust and/or separate from the rubber. When serviced, and air is added, the belt can break, and 'zipper' out of the tire. If you're unlucky, you could be standing close enough to be injured by the steel belt zipping out of the tire. Along with an explosion.
What I've read and seen in shops is that the techs use a clamp on, and then just stand to the side. Not 15' away, maybe 5'.
BTW, over the last 8 years, I've made the mistake of buying this type of chuck: Coilhose Pneumatics Chuck Assemblies Ball Chuck & Clip - 166-CH09 - UNEEDIT.com
from Harbor Freight. Three times! Each time the thing fell apart the first time I got around to using it. Last time was a week ago. They are junk, and if my memory had been better, I'd never have bought more then one from them. Naturally, I'm miles from the store when I try to use the chuck, then time passes and I forget about it. Why they haven't fixed such an obvious manufacturing defect after 8 years is a mystery to me.