Yes, the cross training effect of flying multiple kinds of aircraft makes for a better all around pilot. When you get the feel for a heavy scale plane the aerobats feel light and quick by comparison. Really fast planes sharpen up your reflexes so you feel like you have extra time when flying anything else. A well-trimmed aerobat teaches you what a good maneuver should look like so it sets the standard for doing them with scale and sport planes.

There are a select few pilots in my club that seem to just never make a flying mistake. They can fly in any wind, fly any maneuver properly, and can spot their landings at will. I've watched these guys since I got into the hobby and have found that they generally fly about 5-6 planes of different types. One guy I think of competes in IMAC, pylon racing, and SPA. Another is more interested in scale so he enters at least one scale contest every year but also pylon races. Both of these guys are also instructors so they fly trainers regularly and practice their recoveries from every strange position possible. Also interesting to me is that these guys never bring all their planes to the field. Usually they bring two and only fly one for most of the day, working on their techniques. But they maintain skills over the long haul will a varied collection of planes that's big enough to offer some diversity but not so big that they can't stay familiar with all of them. IMO, one of the common beginner mistakes is to amass too big a collection of planes without enough diversity. Ie, 5 different sport planes or every WWII scale model they can get. A much better choice for improving pilot skills is to have one plane in each category- a sport plane like a 4 Star on Ugly Stick, a warbird, a racer, an aerobat like a Kaos, and something slow and underpowered like a Cub.