if it realy will be only an option then it is OK, otherwise i prethor threadshold. add Storj to coinbase wil be also very good.
You can use a Kraken or Binance which already have STORJ listed if you need for fiat.
coinbase is good because fiat hapen in 10s also i completed all needed procedures, coinbase itself is very expencive exchange but coinbase pro, i like it.
You can ask them to add a token. We do not pay any exchange to list our token, they do it on their own.