If a 15 minute open refund period produced "obvious and intuitive consumer benefits" just think about what an hour could do. You know, like enough to actually test out the app for REAL. Especially apps that are more complicated than flappy bird and, oh yeah, more expensive.
Mea Culpa: though I will acknowledge that a "free" app with in-app purchase, that works well enough to test it out before spending money, is indeed one way to get around the limited 15 minutes to test the app.
But of course those apps are not the problem. The problem the government (you know, the supposedly by the people FOR the people) is trying to prevent predatory sharks from bilking people of money through shady practices like kids games that make it very easy to just click click spend a shed load of money.
"Open purchase window" here does not mean "open refund". It means "you don't have to enter your password again to buy something". Go smurfberries!