When scraping the Binance API I noticed fees being charged in BNB and not in the currency you are trading, as is normally the case. The incentive is a reduced fee. Full details here: https://settle.finance/blog/binance-fees-info/
In other words, it makes sense to buy a bit of BNB if you trade on Binance, to cash in on this discount.
It's also worthy to note that this is quite clever on Binance's part. By making fees payable in their currency, they are instantly increasing the demand for their coin, which will probably push the price up over time.