Electrolytic capacitors in the signal path create harmonic distortion because of the rectification effects of the dielectric, higher ESR, and dielectric absorption.
For a coupling capacitor film is always the superior choice.
But when film cannot be used, because of issues with the larger physical size or greater cost, building a portion of the capacitor from film can help reduce the ESR (like parallel resistors), and it can help with the higher frequency response because the charge moves and redistributes faster in a film capacitor than in an electrolytic. Bypass capacitor is the phrase for searching.