When you discover an arbitrage opportunity like this, it is very risky because the price can change suddenly on one exchange or the other. The second you post something like this and make it public knowledge, the opportunity basically vanishes because the more people do this, the quicker the "spread" between the two prices will shrink until this is impossible (and many of you will get stuck between step A and step B and end up holding some random shitcoin that you now can't sell for any profit.)