Then the buyer takes less risk, the seller still knows they are a 'real buyer' not a freebee seeker because pulling out the credit card is still a commitment, even if you decide to get a refund later.
As programmers, I think we're naturally skeptical of new projects (especially ones that seem to come out of nowhere). This is doubly true when we're asked to pay for something and we can't even try it. We've all heard Kickstarter horror stories and can point to some sort of vaporware that let us down.
Here's a testimonial from Chris Sells (one of six "Microsoft Software Legends" and the author of a number of books on C#): https://twitter.com/csells/status/606141631054540800
Let me know if there's anything more you'd like to know about Alive or the team behind it.
So at least, there's that.