There's absolutely no reason to assume that getting your hands dirty would be "good for you". Playing outside and getting dirty is fun and is arguably great for enrichment and character building, but I think it would come as a surprise to just about anyone that it has health benefits.

When I say "come as a surprise" I mean they would be unable to articulate the exact mechanisms behind the health benefits before being told what they are or that they exist. Liking a thing and presuming it must have health benefits aren't the same.