Very cool! Even full amp modeling aside, this brings in things like separate power amp blocks, captures of drive pedals not on Fractal, captures of "odd" things like weird preamps and tape machines, etc, so I think it's a cool addition even if modeling remains the pull for Fractal.
Re: the Stadium, the effect this will have on that really depends on the form factor and price. I mean, the Fractal stuff will almost definitely be more expensive either way, but if next gen Fractal follows the pattern of releasing the flagship rack version first, and then a cheaper floor version a few years later, that's really a different market from the Stadium and Stadium XL.
Either way, happy for Fractal users. I'm sure whatever Cliff puts out is gonna be amazing.