First: The GoPro can't be used for Agisoft since it uses a rolling shutter.
Second: In order to work in low light conditions and still getting nice quick-shuttered videos, the GoPro increases the ISO to extreme values which introduces incredible noise.
Third: The GoPro has a fish-eye lens which can't be used for SfM.
And because I don't give much about theory, I tried it myself with the GoPro Hero 2 and my Octocopter, just for fun. last year.
And failed.