Two things here:
When I buy software at Best Buy, I dont get to return it in 24hours, ie. games and such...So why should you in the apple store get a refund if you dont like it?
Didn't you just answer your own question? If Best Buy isn't offering a money back guarantee, but Apple is, wouldn't you buy from Apple instead of Best Buy?
Also, being able to control how apps are downloaded and uninstalled, means that Apple can make the system work. Best Buy can't implement it, because you can make a copy and keep the game while returning the disk it came on.
Returns on digital downloads will push for higher quality applications, this is a good thing...