That's Paypal rather than the seller. Seller had probably already taken the funds out of their Paypal account and so the default (only?) way to refund at that point is eCheque.
Thinking about it whenever I've refunded through PayPal for whatever reason it doesn't even give the option of eCheque so you must be correct. I'm sure PayPal could do it far quicker however!
That's Paypal rather than the seller. Seller had probably already taken the funds out of their Paypal account and so the default (only?) way to refund at that point is eCheque.