This is an old copywriting tactic that has been around for decades. It's the "too good to be true" policy. It's just a way to make people think "wow, how does he stay in business!". It really makes you think that their product is very good.

I vaguely remember some book author having an interesting typo related policy. His claim was, for each typo reported in his book, he would start out by paying 1 penny, and for the 2nd typo he would pay 2 pennies then 4 pennies then 8 pennies and so on. It was a crazy claim because if you double your pennies 30 times, it's over $5 million dollars. I can't remember who did this, but how's that for an incentive to buy the book haha.