Churchill was stocky and short, built like a fire plug in fact. And a very good wingshot, semi pro live pigeon shooter,etc.
But, he popularized the 25" barreled doubles after WWI for the simple reason that the market was clogged with long barreled doubles.
WWI decimated the ranks of shooters so there were far more shotguns than shooters. Churchill's XXV was a new niche and the guns were superbly made and balanced. And sold well....
I've shot a couple for a few shots each. Feels lively but not twitchy, and I'd have to think very hard to come up with a better quail gun.
However, most folks wingshoot with longer barrels because they can hit better.
Look at the big money shotgun sports, Sporting Clays, FITASC,and live pigeons. The top guns in all those go with long barrel,usually in O/Us.
If there were any benefit to short barrels for them, they'd all be packing coach guns by Perazzi, Kreighoff, et al.