Why doesn't that count as practice?
The learning psychology field often differentiates practice from deliberate practice, where practice is just about anything and deliberate practice is focused learning.
In deliberate practice, you have to work at near your skill level, you need to apply proven learning methods, it should take maximal effort, you need a feedback mechanism to course correct, etc. A great deal of focus goes into creating effective mental models and intentionally removing ineffective mental models. It requires good coaching. As you progress in expertise, your practice should involve more risks and failures. (And there's still much more to be said here)
Gigging and noodling aren't going to make for efficient practice as it likely won't be full concentration, won't involve feedback, won't involve challenging material at your skill level, etc.
Also, you can spend 10,000 hours jamming alone in your bedroom on same set of guitar tabs and make shockingly progress compared to someone who spends just a few hundred hours intensely studying music books with a metronome and tape recorder.
Mind you, there can be some value in repetition starting out especially if you make regular minor adjustments. But for someone already at a high skill level, just doing the same old activity probably won't help their skills much.
As an instrumentalist, I can choose to play my part ahead of the beat, behind the beat, right on time, I can choose to embellish my part or play it as written, I can improvise a solo vs play something pre-planned, I can subtly vary the intensity of my playing, all while my bandmates are tweaking their performance in real time, too. There's also the telepathy you tend to develop with your bandmates when you're unable to stop a show and yell about mistakes or forgotten parts :)