1. The prize itself makes zero sense as a prize in _physics_. Even the official announcement by the Nobel Prize Committee, taken at a face value, reads as a huge stretch in trying to link neural networks to physics. When one starts asking questions about the real impact on physics and whether the most important works of Hinton and Hopfield were really informed by physics (which is a dubious link to the Nobel prize anyway), the argument stops holding water at all.
2. Some of the comments mention that giving prize for works in AI may make sense, because physics is currently stalled. This is wrong for several reasons: 2.1. While one can argue that string theory (which is, anyway, only a part of high-energy theoretical physics) is having its "AI winter" moment, there are many other areas of physics which develop really fast and bring exciting results. 2.2. The Nobel Prize is often awarded with quite some delay, so there are many very impactful works from 80s which haven't been awarded with a Nobel prize (atomic force microscopy is a nice example). 2.3. It is wrong to look at the recent results in some sub-field and say "okay, there was nothing of value in this field". For example, even if one completely discards string theory as bogus, there were many important results in theoretical physics such as creation of conformal field theory, which was never recognized with a Nobel Prize (which is OK if Nobel Prize is given to other important physical works, but is quite strange in the light of today's announcement).
To finish on a lighter mood, I'll quote a joke from my friend, who stayed in physics: "Apparently the committee has looked at all the physicists who left academia and decided that anything they do is fair game. We should maybe expect they will give a prize for crypto or high-frequency trading some time later".