I think it's foolhardy to assume they are vestigial. Did they test other spectrums such IR, UV, etc? Did they test other phenomenon such as muons? Evolution wouldn't have put something there if it didn't serve a function.

Isn't that part of what it means to be vestigial? It used to serve a function, but it doesn't now.

Vestigial has often meant “we don’t know/haven’t identified what function this serves” … yet.

The famously "vestigial" human appendix actually serves as a seed vault for replenishing gut microbiota after a gut disaster, I hear.

Unfortunately. As with the appendix.