Devs, don't you plan to make your own slack channel? It can increase your score at different ICO trackers.
I don't know if a slack channel will increase your score on ICO trackers, but EO.Trade has a Twitter account, a Telegram Channel, a Reddit channel and many more. For a slack channel, you will need additional team members, which is in my opinion not necessary.
I think you're right, I don't see any need for EO.Trade to own a slack channel. They already have channels promoting this project. As said above, few of them are sufficient