Sorry but I disagree about the water from personal experience painting with a dry brush versus one after I washed it. Especially on ceilings, you get diluted paint running out of the ferrule and it makes a mess. When it's wet, it thins the paint, lowering the viscosity. I can use a dry brush all day and not get paint to the ferrule. Use a wet one for an hour or two, and it does. And it's worse with epoxies and solvent based paints. You can see for yourself with a little experiment. Take two similar brushes and wet one of them. Put a 1/2" of paint in a cut pot. Set the brushes in the cut pot and walk away for an hour. When you come back, you'll see the wet bristles have paint bleeding up the bristles well above the line it was submerged to, while the dry one won't.

Looking around on Google, it's a mix of some saying you should, and others saying don't do it. It depends on which source you look at. Neither Sherwin Williams nor Purdy recommend it, but I see people on quora and other places saying you should. So I'm gonna go with the guys who make the brushes instead of of randoms on the internet. Nothing against you if it works for you, but I just imagine a person who's not a pro painter making more of a mess with a wet brush. And all the sources that do recommend it say it is too help with cleanup. Other sources say it's bad because it dilutes the paint. So I wouldn't recommend to the average home owner.