MyHeritage has implemented a version of it to very quickly and simply colourize old B&W photos and right now it is free to anyone, without even logging in!https://www.myheritage.com/incolor
I spent many, many hours colourizing an old B&W photo using GIMP. Using the MyHeritage implementation, it took about 5 seconds to do the job. Admittedly, the colours using the GIMP method are more accurate, but given the simplicity and speed of DeOldify, it is truly amazing!
It would be really neat if GIMP could beat PhotoShop and other photo editors in implementing this tool. I believe that the MyHeritage version just uses a default set of parameters. Within GIMP, you could provide the user with the ability to adjust those parameters to do a better job.
I am not sure if this is the way I should make such a request, but if I am going about it the wrong way, perhaps someone could let me know the correct way to do so, or better yet, forward this to the appropriate people.