Ok, first of all most of the stories of masters being inspired to immitate animals after watching fights are just that... stories.

There is little documented evidence of most of these founder's myths. Furthermore there is a story which is quite formulaic across multiple styles.

Master (a) was out (meditating / going for a walk / recuperating after getting beaten) when he observed animal (x) fighting animal (y). Suddenly master (a) realized that the strategy used by animal (x) could be applied to fighting to succeed in defeating antagonist (b).

Now we also know that there is a certain shamanistic tendency in alot of Chinese folk religion. And we do know that many of the figures who are ascribed status as founders are figures of religious or pseudo-religious professions. Based on this we can infer that it's possible that shamanistic folk-religious tendencies snuck into the martial arts through these purported founders if they were, in fact, anything like the legends of them describe (monks, nuns and hermits).

It's also interesting to note that the most directly immitative aspects of animals occur within the empty-hand forms of these martial arts; this is of particular interest as we do know that for the majority of the history of CMA empty-hand techniques were considered secondary to weapon techniques.

So I propose this hypothesis: animal immitation in CMA has nothing to do with fighting better, notwithstanding founders myths, but is, in fact, a carry over from shamanistic practice that, while based on animal immitation, is not in order to create better fighters but rather to evoke the "spiritual" qualities of the animal in question.

At this time I don't have a research method to falsify this hypothesis and so it remains open, a matter of opinion, based on the above reasoning, and not irrefutable fact.

As for the original topic: Videos are of limited use. Certainly they provide no opportunity to test. That won't happen unless you have a partner to work with at the very least. As a peripheral study-aid they don't hurt.