One of the staff at Bintel suggested that they are not the same. With very short exposures if the signal is not there (equipment & setup) then it doesn't matter how many you stack. If you want to get faint detail his suggestion was to go as long as possible.
It's not relevant to this post but for dso's i aim for between 5 and 10 minute subs. That's with a cooled asi2600 mc, a short focal length and guiding.
Attached is a 360 sec fit frame directly off the camera. It has not been debayered. The quality is extremely low as to get a jpeg i used the screen snipping tool and the resulting jpeg is only 47kb. I am not convinced you would get anywhere near the same detail if you stacked 100 3 second exposures?
If this was true and I could live with the stacking time i would do it every time, stack a few thousand 3 second images and avoid guiding errors, seeing and get wonderfully round stars.
YMMV this is only my opinion
