I know all that, Phil. I just don't know why it's an unfair ask for a professional caddie to know how to play the game a bit. Personally I prefer Evans Scholar caddie programs, but can understand why a resort would go with adult, professional caddies. It's easy to imagine people who rarely take caddies thinking it's a bit awkward to have a 15 year old carrying for them. If a resort is hiring professional caddies, they have to have some way of measuring their ability to understand strategy and basic playing skills. I think a handicap requirement is a fair enough way to do that. It's obviously imperfect, but it's probably as good an option as any.
I'm sure there are some 20 handicappers who are great caddies. But in a random drawing, I like my odds better with a 5 and certainly don't begrudge a resort owner for making it a requirement that a player understand score posting and be in the top 50% of people who do so. Again, I just think a better player is more likely to give better advice on strategy and reading greens, if nothing else.
As for the initiative itself, it's obviously a bit half-hearted. I'm sure the course doesn't want to cut too much into their cart revenues, so it's not like they've made walking an excellent deal. But it's still not a bad thing, and as Josh mentioned, maybe the mileage credit will get more merchandise bought or something. Anyone who knows me knows that I'm more than happy to walk 6 miles a day for $300 at the end of a year. Getting a dollar per mile sounds great to me, though I'll bet it's more than a six mile walk around that course and I'll bet I can prove it at the end of a round too.