Even if it doesn't become 'popular', you will still have that sense of achievement and something to show for all the work you've put into it. Most of the time when I do programming work, how much I get paid isn't the most important thing; it's seeing my work in action

As long as you can prove it's safe and secure and it has the features I use often, I'll give it a go :P

(You have to be even more careful with open-source software as it's probably even easier to exploit, and some people are less honest that others when they find holes).