I don't understand so I am asking?
They are not as great as they claim. They can be quite handy, but they are frusterating beyond belief.
Perhaps this subject is best for another thread, so I'll keep it short. A few gripes:
* They lock payments for an unreasonable amount of time. Users routinely cannot access their money, which for people who make things for money, is severely limiting because it limits the ability to get supplies.
* They charge for everything you do, and since they are owned by Ebay, using them with ebay results in you getting hit twice for your money
* They are not a bank, so they do not have the protections of a bank
Some of these apply to sellers (the first), ebay users (the second) and everyone (the third).