I wouldn't call that laughable, that's 50% higher than the max altitude the F.35 can retain control at. It's number 13 on https://www.militaryfactory.com/aircraft/aircraft-ranked-by-..., with the likes of the space shuttle, the X15, sr71 (30 ft higher), the space shuttle and experimental planes: few production "planes" can fly that high.
Admittedly, it isn't that useful anymore. Missiles can reach that altitude fairly easily, so it does not provide increased survivability anymore, and spy satellites, though less mobile, are more useful for day-to-day operations. But it is still a fairly unique capability.
I'm sure that wasn't the focus of the design, but I can also imagine that its balsa wood structure provides a lower radar cross section as well. (Edit: I made a mistake: looks like it's made of aluminum, not wood. Probably had another plane in mind)
An interesting anecdote was this interception of a U-2 over France in 1967 by a rocket-assisted Mirage. The pilot photographed the U.2 with a hand-operated civilian camera, leading to a diplomatic incident: https://theaviationgeekclub.com/that-time-a-rocket-booster-e...
Today it's probably for hire for major events like a big match.