Developers know that there are some people out there who share a vision and have faith in the dev team to deliver; people who are eager to help in any way they can. Money is often the easiest way to assist, and offering an early alpha for money is the obvious choice to give those people a path to be involved in the development in a tangible way while fueling the development of the game - which, you might be shocked to learn, costs money. That money has to come from investors of one sort or another. We're fortunate enough to live in an age wherein we the gamers can choose to BE those investors, and cut out the middle man in the process. Middlemen who often push their own agendas to the detriment of the end-product. Apart from the money, paid alpha access also has the benefit of filtering the initial testers of the game down to those who are literally invested in making the game a success. You tend to get much more valuable, productive feedback from that group. If that doesn't make sense to you, don't stress over it. It just means you're not part of that group. If the game, the company, or the idea isn't compelling enough to make early investment appealing to you, by all means - do NOT spend your money on the alpha. Wait for the finished product, THEN decide if its worth your money.