https://components101.com/articles/decoupling-capacitor-vs-bypass-capacitors-working-and-applications#:~:text=The%20Bypass%20capacitor%20is%20used,spikes%20on%20the%20supply%20lines.
The main capacitors, or AKA "filter capacitors" in an amplfiier will together with the power transformer(s) influence sound quality overall, but most importantly have great impact on the level of clarity and transient response in fast-paced music; also important for resolving nuanced details in slower tracks.