> No, they don't. There doesn't need to be an arbitrage. If you have 10 USDT and I give you 9.90 USD for that...nothing else needs to happen.
I'm not an expert, so I might be wrong (seriously, not sarcastically). I _think_ this is technically arbitrage even though you never complete the loop.
It's arbitrage if you can close the loop with little or no risk. Preferably immediately if you already have a buyer lined up. Otherwise, you incur more risk -- you might be caught holding the bag when the music stops.