I do Kickstarters for several artists I'm a fan of for print runs. Essentially the work is finished, or near finished, and the artist will crowdfund to get prints made to sell, they usually get enough funding to do about three fold what's ordered in the kickstarter. So the KS backers are already taken care of, and the remainder they'll sell at conventions over the next couple of years.

And yeah I've backed a couple gadgets too, they never came to market. So? It was like $35 total, and maybe two a year. I think I'll be alright.

As with most things, if you can't afford the risk, don't take it.