This is both ambitious and seemingly not intractable which is a rare goldilocks combination.

As some contrast, consider something like GNUStep. You are never going to get macOS out of GNUStep, no matter how hard you try, because it is too high level (Cocoa) while simultaneously too ambitious. Similarly, with alternate kernels like ReactOS you will never get full replacement of Windows because it is too ambitious and intractable.

The intersection of this project though, it is a cunning insight in using the hardware support of Linux and shedding the graphics layer for something a lot simpler with a minimal kernel module to support the existing mechanics of BeOS. This is more in line with wine, which is and has been useful for a long time, but is even easier. This doesn't mean it will achieve massive user base, but it seems like it will mature fast enough into something dedicated fans can enjoy and use productively.