Rocket.Chat is a real world chat client that seems to have some success and they just decided to delegate an important part of their stack to a third party project. What better validation do you expect than that?
Rocket.Chat still maintains its own full frontend and backend. With its own API's and integrations etc. But gains a new ability to communicate with anyone out there also using the Matrix protocol. Regardless of what Software they are running.
So say your company has Rocket.Chat running and then you start working on a project with another company. You can create federated rooms and collaborate.
IMO its very much a strategic advantage to have federation support in your tool.
I personally view this as an important move for the future of the internet and modern decentralized communication.