Money moves in dinars from end to end, so there is no conversion between your bank and your balance. The ways to pay come down to two groups: instant bank transfers and cards, and cash paid in at a payment point.
They differ not in what arrives, but in what they ask of you. The bank route needs your bank to pass that kind of transaction, and the counter asks only for the trip to a payment point.
The differences show on the withdrawal side, and one step decides the rest: proving who you are. A licensed operator in Serbia is legally required to verify a player before paying out, so it costs a few minutes on day one and a weekend if it waits until a payout is due.