The main thing is that there is already at least one exchange, probably it is just now an opportunity for such as I, new users who are interested in Aro and other coins on the market to buy them. I hope soon there will be new additions to the exchanges, as this would increase the volume and add new users.
Mercury80 told that next exchange must have at least 10m$ volume
A new exchange addition always brings in new attention especially with listing on CMC for example. The most important part is actually creating some need for the coins and some initiative holding them. For such an demand there has to be options to spend or use the coin