Let's do this the other way around.
Let's say that customer to merchant transactions are only 1.3% of all money transfer in the world, cards, wires,pp.
What would the rest of 98.7% be?

Personal transactions for relatives? Sending money to the stock market? (lols) Deposits? Sending money to your safe?

I'm confused

I already mentioned it's forex trading, so euro > dollar > whatever > euro > circle > around > dollar. That's the large majority of fiat money transfers. Why would that be any different than dollar > bitcoin > dollar?
Maybe you mean the number of transactions, then indeed I have no idea how many transactions are used for 5 trillion worth of forex trading per day. Automated systems could make billions of trades, or it could be just a "few".