Credit cards, hmmm. Didn’t occur to me because I don’t use them, but sure, that’s another way. I just checked randomly some known open source projects (Gnome, Kde, Gimp, Krita, Inkscape, Linux Mint). None of those offer donations by credit card. Must be a reason, I guess.
None of those are "serious online business"es, though, but community projects.
Supporting debit cards at least is a must if you want to be serious about making a lot of money in donations. Why, because pretty much everyone here who has a personal or business account at their local bank should have one. Please don’t give the whole “banks are evil” shtick as a reason to not do that because the vast majority of banks are not of the ‘too big to fail’ type.
There’s a few good software-based solutions out there that can easily set such a system up for you, so if the BF doesn’t have something like that set up then they need to get going on it.
Please don’t put word into my mouth. I said:
From that you can see that I actually prefer transferring money via banks.
Bank transfer is normal where I live, credit cards aren’t, that’s why it didn’t occur to me. I’m fine with it though if somebody wants to use it. None of my business really. 
I wasn’t referring to you when I said that, it’s just that fans of FOSS tend to have a higher likelyhood of being against big corporations and, by extension, big banks.
Also, I mentioned debit cards mainly, the difference compared to credit cards is that they draw directly from your bank account instead of from a line of credit.
Ah, ok, I thought you were, my apologies then.
None of those projects has got a commercial side with the size and ambition of the Blender Foundation’s, with a relatively big e-shop, donation and subscription schemes. I don’t think that using bank transfer for online business is the way to go for obvious reasons. Paypal made sense in the beginning when the Blender Foundation needed to set up a quick hassle-free international payment gateway and Paypal was more or less the only option available. It does not make sense now and many people don’t feel comfortable working with an organisation (Paypal) that epitomizes every thing wrong about doing online business: abusive TOS, arbitrary ruthless behavior, disdain for consumer protection laws, understaffed complain system, poor security, etc.
I agree about Paypal, I won’t use it, but what’s wrong with bank transfer for those who have the infrastructure? It’s working very well for me for all my online purchases, at least in the EU. For people outside the EU another option like credit/debit cards would be good, though, I agree also.