From deposit to payout the money stays in dinars, with no conversion on the way. However many names the cashier lists, the groups are three: bank routes, vouchers with counters, and the shops themselves.
They differ not in what arrives, but in what they ask of you. For the bank route it is enough that your bank does not block the transaction, a voucher needs no card whatsoever, and for the counter you only need to reach a payment point.
The differences show on the withdrawal side, and one step decides the rest: verification. The law requires a licensed operator to verify a player before it pays out, so doing it on day one costs a few minutes while leaving it until a payout is due costs a weekend.