In finance, 1 BPS is 1/100th of a percent. So Apple could be pocketing ~0.2% on all transactions.
The US does about $12B in card transactions per day. This means that for every 1% of US transactions it captures, Apple could add ~$80M to the annual revenue which is a very small amount against its $140B revenue. Yes there are international markets, but still this is not done for profits by itself.
