An interesting find, thanks for sharing. I made some tests and was surprised by the results for skin tones, it does a nearly half decent job for base colours. It does retain the original feel of the photo and does not remove noise/grain etc.
What i would say as someone that likes to colour old photos; Is it does not colour backgrounds and misses a fair few spots on the people subjects, especially where shadows and contrast are darker and also fine detail like jewellery. It does not take into consideration lighting within the environment. It does however deal quite well with the hair colouring, but wouldn't know if someone should be redhead, mousy brown, dark brown etc etc.
It could be a handy tool to kick start the base colours of skin colouring but not much more than that.
I think in the next few years these algorithm based auto colourisation tools will be perfected...
If your photos came out well when playing with them, then that's great and it is indeed amazing to see how some of these BW photos can look with a colour splash