Seriously, if any site owner has even a half of a brain, he should stay away from this shit.

Disposable email exists for a reason.

That is not true at all.

If your site is just a chat forum and you don't mind spammers, sure let people use disposable emails.

If your site involves money or auctions or credit cards.. letting disposable emails in can be very costly.

If a quick-and-dirty domain check on an email address is more secure for fraud detection than credit card data, then that says a lot about how broken the whole credit card system is. No surprise, of course. Sad that Bitcoin blew its chance to replace this crap.

You don't replace, you use it in addition. Layers of security.

Now if you want to spam 500 million credit cards on my system, you are going to need to at least make them from some common domains, which I can block down the road. If you are using an email hiding service, way easier for you.

Not sure bitcoin matters, if I had users paying with bitcoin in an app I would STILL blacklist certain email domains.

You probably have encountered even more sites that use this, and didn't notice because you didn't try giving them a throwaway address. Which might be exactly the point of using the filter.