Assuming you even get this up and running if you are below 5% you'll be successful in terms of people will use it but you'll always have tons of charge backs so good luck.
Yeah, that is the insanity of such a business. And this guy sounds like exactly that,
a guy. Hopefully this guy realizes that once he starts up a business selling bitcoin by credit cards, he's now open to all sorts of regulation. Hopefully this guy knows the law (I don't, but I'm just saying here). Everything varies by country, of course, but I doubt there's a country in existence where they wouldn't tax and regulate such a thing to death.
Plus there's already tons of competition. So good luck, but cpfreeplz probably is estimating your chances optimistically. I'd say they're less than 5%...but for your sake, hopefully I'm wrong. It's definitely a worthwhile service, and we need more options.