that indeed you are correct...at least for some things!
In terms of evaluating some of the key fundamentals it is nice for "after the fact" to see how close you are. The face on view is great to evaluate things like the first move, lag, and ( if you have a fast camera ) impact. But this little exercise was helpful to me in the eventuality I use video as an aid in teaching - gotta be real careful before making any comments or suggestions based on video. Now I'm thinking two or perhaps three different camera angles all running at once is best.
Its funny though - lots of times watching golf when a pro hits a bad one, and the commentators say "Lets take a look and see what happened", they can't even tell, make some lame comment, which from watching the video, you cant even see the difference between the bad swing - looks as good as a good one.
Makes me thankful for my mirror!