I'm actually using Binance and almost all coins there have an option of these from the Binance chain, TRC20, BEP2, and ERC20 on withdrawal.
I'm using some of them TRC20 and BEP2 just to reduce the withdrawal fee when transferring them to another wallet or in other exchanges like Okex they support TRC20 for depositing.

I think the reason why they have these options is to help the community or traders to get fewer fees if they are going to withdraw them or transfer to another exchange. This is their solution for congested blockchain networks and high fees.