I'm familiar with the use case for this. I don't want to use the same keyboard for work (typing) all day that I'd use for gaming after work. I also don't want TWO wired keyboards. So if I can have a wireless gaming keyboard that I set off out of the way during work, and then can push my main keyboard (wired ergonomic membrane) out of the way and use the gaming keyboard (wireless mechanical), I have the ideal input device for each use case.
(If the Microsoft Ergonomic keyboard came in wireless, I'd get one - one less wire making it sub-optimal when I'm ready to swap keyboards.)
(If the Microsoft Ergonomic keyboard came in wireless, I'd get one - one less wire making it sub-optimal when I'm ready to swap keyboards.)