I'd love to find a developer that does what this claims, and I'd like to test this if anyone decides to bring it in to the US.
While granting that there's no real magic in developers, some do, in practice anyway, allow shooting with good results at speeds scoffed at by some. It's funny - if someone DID formulate a developer that gave a true speed increase of, say, three stops with common films, or even one common film, as measured by the usual densitometric methods, no one would really believe it. People who needed what it could do might, might, find it and use it, and the densitometer heads would scoff at them and probably refuse to test it. Note that I'm not saying this DOES. I doubt it very much too, at least in terms of "real shadow detail speed" but I'd be willing to try it and even if "real shadow detail speed" isn't increased much I'd also evaluate it in terms of what available light photography looked like when using it.
One example I use is Diafine. People have argued for a long time about whether the speed increase is "real" but what I have found is this: when I shoot Tri-X and develop in Diafine, if I shoot it at 400 the negatives are dense, flat and grainier than when shot at higher speed. They look for all the world like they are overexposed between one and two stops. When I shoot it at EI 1250 (as high as EI 1600 as the box claims using daylight, like an overcast day, and more like 1000 under tungsten - 1250 is a good all around compromise) they look much better and print much better
for my purposes. No matter what a densitometer might say, that's the final criteria.
If Diafine gets me negatives I like from Tri-X at 1250, I'm willing to entertain the notion that another developer might get equally good or better results at, say, 2400 or 3200. Above that my skepticism increases as geometrically as the film speed scale itself, but I'd be willing to be proven wrong.

However, with the quality I get from Delta 3200 at 3200, I don't see the need to push Tri-X to that speed.
"Who needs it" would be me, and I suspect others. I'm always running into situations where I'd love to shoot by available light but it's just too dark, which is one of the big temptations for me to break down and finally get a DSLR.