Interesting discussion, one that seems to pop up again now and then.
The other discussion might be diminishing returns as well as your cameras maximum dynamic range limits (ADU limits)that determines which method suits and 'how many hours is long enough'...
I might have my understanding wrong(learning continues), but I couldn't see how multiple short exposures amounted to the same results as a single long exposure method, it just didn't make sense to me unless the light gathering conditions could be met with both instances where the same sum of signal brightness is gathered.
But if you're averaging you can only have so much signal to weed out of the noise in the end?
I see it that The count total of short exposures you'd want to take could work two ways, one would be using a light bucket with a low end camera, your ADU might blow out so you take say a 5min exposure, then you take multiples, as many as you want but your only improving the SNR of limited range of signal over the noise.
Then you use a high end camera with a huge well depth, as long as the tracking mechanics of your equipment allows you to with good accuracy, you could image for an hour. Here your SNR also is improved and you're seeing an increase of the signal brightness over time, and this can also be improved more by improving the SNR again using multiple images and averaging them.
But from both scenarios depending on how long you expose for with the cameras well depth and the telescopes ability to gather photons slow or fast, every instance has a point of disminishing return that is limited by your camera and telescope.
So whether it's 20hours of short 5min exposure stacks, or 20hours of 60min stacks, they can never be equaled.
And considering that, what you decide on in the end has a diminishing return value of how much signal you capture, it's just the method you decide on to get there and how dark a site you have that can capture light fast than noisy light polluted sites.
Edit: I see you guys have touched on this already at this first posts
My bad?