There aren't many features that can really bring a community together like the ability for the community to communicate with itself. Live chat-rooms are one of the best ways for an online community to interacts.
Here, people could speak on what they're posting in the marketplace, they could talk about news & upcoming market trends, help teach newcomers about Apollo and some of its features. To me, there are more reasons to implement a chatroom than not to, but I am uncertain on the technicalities of what it would take to put a chatroom into a blockchain based platform.
The chatroom itself would either need bots like in telegram to automatically quiet people who use certain language or simply have mods aimed at keeping communications smooth and respectful.
This feature may be unnecessary, but could be of great value.