I worked at a place that did this - separate team for the new project with their own eating area - and the amount of goodwill it blew was amazing. People who'd worked together for years became resentful of each other. It created a "we know best" attitude in the new team, who then spent months playing with cool tech and failed to launch. They were months late by the time I left.
It's a fine line to walk to carve out a team to "move fast and break things."
It can be valuable in an org that has gotten bogged down with process that is often in place for good reason, or that needs to focus on longer-term things.
But when you do carve out that team, extra care needs to be spent figuring out how to integrate their efforts and culture with existing teams they need to interface with at various points. Likewise, it really needs to be positioned as a benefit for everyone.
