ETH 2.0 staking on Binance vs just buying BETH

I’m interested in staking ETH, if I go through the staking portal on Binance I’ll receive BETH at a 1:1 rate from the the ETH I stake.

But, I can buy BETH directly with the ETH/BETH pair at a rate of 1:0.95

So I get 5% more BETH for my money by buying it directly, Binance customer support tell me I still get the rewards doing it this way – so what’s the catch? Why have the staking portal at all?