I'm interested to see how this might affect RTMM (and MFC) in the medium to longer term. Until a product is released a lot of this is marketing, with more recognition by MS of their core audience than we've seen for a long time.
Of course it looks fantastic but I've recently noticed an interesting thing. I've started using X-Plane as well as P3D and with the right combination of add-ons it's looking more like MSFS2020 to me than P3D. But, I'm still enjoying P3D, once again with the right combination of add-ons I think it still looks decent.
Of course I may feel differently when a product is actually released but there are a lot of pros and cons to consider and no reason why I couldn't add it as yet another sim, getting benefit from all of them.