…or mybe they could send someone to your place to give a presentation and if you like it, install it on your server
I am certainly not THAT bad 
Seriously, I think it is far from unreasonable to expect in a product announcement a minimum of information about what the product actually does.
See for example in the 2018 announcement about the initial integration (in https://nextcloud.com/blog/rocket-chat-and-nextcloud-announce-partnership-and-integration/)
The integration allows users to post files from Nextcloud directly into a chat channel, enabling seamless integration between chat and file handling. By sharing project documents in a project’s chat, collaboration is simplified. Home users can easily share pictures or documents with family and friends. More integrations, that go even further than this latest iteration, are in development.
And yes, I had clicked on the links. It gave me information about what Rocket.Chat does, but absolutely nothing about what the Nextcloud-Rocket.Chat integration does.