The more exchanges in the market mean we can choose what is the best for us to use. More choices for us to pick which one is the best and more easy to make some arbitrage with some exchanges..
One of our advantage as traders is this arbitrage opportunities, if there's a lots of exchange to deal with we can perform this trading strategy, find some good edges between those available exchangers but also be aware of possible negative side of this practice, there's also scam exchange or bots that manipulating the trade process around.