I would imagine managing liquidity for such a large exchange would be a bit more complicated than that, even if they don't use their liquidity to route payments. Like making sure they have enough inbound/outbound liquidity and connecting to good peers.
I think that's a bit above Binance's usual forte of listing yet another ERC-20/BSC shittoken.
Also I should mention that Binance by default still uses Legacy addresses. It's so frustrating. The default address you get for deposits is a legacy address (i.e. the one the vast majority of people will use). Segwit address is listed as "BTC (Segwit)" which probably makes a lot of people think Segwit is just another sidechain like their BSC stuff.
Even if the reason was seemingly compatibility with 8 year old wallets that still haven't implemented the new address format, they could at the very least use P2SH segwit. Instead the chain gets clogged up every time Binance decides to consolidate.