Can't and don't fault your position at all. Reality is that, short of a type specimen, there needs to be enough mutually supporting evidence from a single encounter to be irrefutable. To my mind this indicates at least both video and DNA (not photos, because a still can be readily faked, whereas a series of motion frames provide physiometric data that is either consistent, or is not - and, preferably, the video shows the deposition of the DNA). The means by which the DNA is collected also needs to be well documented to later demonstrate proper handling and chain of custody.
Footprint data and other secondary forensic evidence is of lesser value because it cannot be tied directly to the individual that left it without the individual itself to compare it to. It is, however, icing on the cake if the primary evidence (video and DNA) are already available.
I don't mean to denigrate footprint evidence at all. The body of footprint data has provided a lot of meaningful information. It is just that any individual print, or limited number of prints can be faked, and so, for a specific encounter, it needs to be coupled with enough other evidence to preclude the possibility of a hoax.