I think they're gorgeous, and fascinating. I don't think they should eclipse pure womas or carpets, of course, but in terms of what we just learned from that cross, it can't be beat. Now, of course, the next step is to find out if these hybrid offspring are fertile.
So long as their bloodline is kept track of carefully, hybrids aren't terrifically different from any of the color morphs--you wouldn't want those loose in the wild, either.
If this was being done in an area where womas or carpets were native, there might be more cause for concern...as it is, those are some BEAUTIFUL snakes, I can't want to see what they'll look like as adults!