They're beautiful pets, but personally I wouldn't breed them. The female is a possibly a combtail at best--I find it easier to see whether or not they're combtails by the ventrals, which she has tucked up in the picture. The fry wouldn't look as nice because the spread of the caudal would be narrower due to the VT influence, and the web reduction won't be as dramatic as a crowntail's should.
Those would be reasons enough for me, but each fish alone wouldn't be what I would consider breeding material. They both have a lot of red wash, the red wash is very difficult to breed out and it's not something people want in a steel blue betta. The current trend is also for masked bettas rather than black faced. Personally, I think your fry would be very difficult to find homes for. If you do decide to breed them, you should probably remove the female before she releases all of her eggs so that the spawn size stays small.
As pets though, I think they're beautiful. The male's face has a lot of personality to it and I love steel blues.