We're encouraging people to use cash or cheques wherever possible. The problem with PayPal is that it levies charges on the recipient of money.
Actually, I
think there is no fee charged to the recipient if the money is sent from a bank account, as opposed to coming from a credit card. But it's no problem to send a cheque. Certainly I don't want my donation diminished by a service fee (which may be a necessary evil in life, but that doesn't mean I have to like it...)