Some electric guitarists can get a bit overly mystical about their amps and effects pedals and all the minutia of the tubes/opamps/capacitors/etc within, but I suppose that's in the same realm as audiophilia. Of course, all that gear is usually intended to operate very far from anything approaching linearity and fidelity or anything objectively measurable, so maybe all that stuff matters more, but without seeing someone distinguish them in a double-blind test I'm very skeptical that you could tell the difference between two brands of film caps.
I've never heard a musician talk about film caps, or any caps for that matter. Some might, but I've never heard it.
Musicians are concerned with how the music they are making actually sounds in live performance and in the studio. I believe it was Ray Davies of The Kinks who, in an effort to get the distortion he wanted, reached into the amplifier and tore the speaker cone. And
voila! We got "You Really Got Me", one of the great British rock songs of all time. I never heard of him comparing the sound of a torn Jensen speaker cone versus a torn JBL speaker cone.
But creation of distortion as an element of one's sound is a very different thing than the concern someone listening to playback at home has for distortion. (For that matter, I've never heard of a guitarist hunting for magic NOS tubes. The ones I know tend to get whatever their local music supplier has in stock. Meaning new, meaning Russian.)