I have helped a few people along these same lines. I ask the person very sincere and credible in every way when claiming to have seen an alien craft, “What did it smell like?” There is never a smell. There is no sound. No exhaust. No wind effect on the trees nearby. “Well, I can’t tell you that you didn’t see something, but I can say if whatever it was, it can zoom across the tops of the trees without shaking them at all, it probably can’t hurt you!” You confirm something anything with multiple senses not just vision.
In both the Ariel School and Westall School UFO incidents, people reported an odor of sulfur. Same for others.
I do not deny your premise - that sight is not everything.
However, one person cannot record the smell and accurately relay that exact smell to someone else. People can record sound, but in most UFO instances they rarely do and/or the distance to what they see from where they stand is so great there is likely no local sound that seems to be identified with the object. The object does not land so they cannot touch it and even if it did land and they touched it, we do not have super objective “touch recorders” we only have human’s subjective touch descriptions.
So, that does leave sight, and what was seen and EXACTLY what the object looked like. BUT that one attribute that can be done and can be done clearly is usally not done or not done clearly.
So any kind of “evidence” that is transmissible with complete transparency is always absent.
Any other kinds of “proof” may render a “belief” that is “true” to the believer, but that does nothing to convince anyone else.
Only the unmistakable pictures will start to end the mystery.