Not allowing Paypal payments is something I would never consider. Unless you are trying to cut down on revenue by about 20%.
I have about a dozen credit cards myself. (Holy Crap!)
However, when I shop online I use paypal. I prefer it.
A: Its more secure.
B: All I have to do is log into my paypal account, and click a button or two to make a purchase. don't have to enter my credit card number, my exiration date, my CVV code and blah blah blah.
I am always very disappointed when making a purchase online and the merchant doesn't offer paypal.
When I first opened my onine stores, I didn't use it. Once I started accepting PayPal payments, My sales went up by about 20% almost instantly.
Businesses also do use it. I get orders from many of the major fast food chains, Institutions, government agencies etc. Believe it or not, many of them use PayPa as the prefered payment method.
If you do alot of shopping online, a paypal account is the most convenient payment method on the internet.