It's the primary (and some feel it's the only) weapon in wing chun and drills, either partner drills, or solo drills require a lot of chain punches being thrown. Once you're past that initial learning curve, chain punches do feel quite natural and can be quite powerful.
Looking at the concept of chain punching, is the idea of chain hitting. Combining non stop attacks from all weapons - punches, kicks, elbows, knees in a continuous flurry. It may not look like chain punches anymore..and may not even contain chain punches. the concept is functional and that's what matters.
But have you tried this before? Have you tried training this way? It certainly wakes your body up - and also tells you how your body is quite limited to chain punching, i might add. It's a crude awakening. And it's also freaking exhausting, draining your energy reserves quite fast.
You gotta make each hit count - no rabbit punches here - it's incredibly difficult to do. Most people would only be able to throw 1, 2, MAYBE 3 punches max at full blast, and after that they're outta steam...or the punches/hits thereafter are pretty much harmless.
If you don't know what I mean, I think you should try it. Try to chain "hit" not just chain punch and at full capacity - make it count. Do this for 30 seconds and see where you're at on the stamina level.
The answer may surprise you.
Until then.