maximumpower
I am curious, how does a compressor "... cover up musician's mistakes"? I have heard this before. Does it have to do with the picking hand? In that it levels out the picking dynamics?
My point was based on the ignorance of people who happily sound off about what they think compression (or distortion/fuzz on guitar ) "does" despite not having a clue what it actually is or does. A typical example would be that "electric guitarists use distortion because that way their wrong notes coan't be heard, never get away with that on a proper (acoustic) guitar". In reality of course a highly compressed electric guitar is actually harder to control than an acoustic because of the need for much better control and string damping to prevent chaos. And compression/distortion makes every glitch painfully obvious.
It's an attitude that's died out a lot over the last 20 years, largely as the generation that held it have died off. Though there are still people around, at least in the UK, who come out with it.
The same kind of people can be heard saying that using MIDI takes all the skill out of music because "MIDI does it all for you" and similar nonsense about using computers (which apparently just make all the music for us). Again, they have no idea what MIDI or a DAW actually is.
One way compression can cover up mistakes, as has been said, is that on guitar or bass it can compensate for a very uneven picking ability. Personally I think that there's a bigger danger in always using compressors on guitars which is why I groan when I see beginners saying that they bought a compressor (or distortion pedal) and leave it on all the time to sound more "instantly professional".
If you learn to play electric guitar with a permanently on compressor evening out the volume and attack you'll never learn how to make the instrument truly expressive, how to alter tone with just your fingers or how you can take a well set up amp from clean into overdrive at will by how you pick or finger the strings alone. It's throwing away much of the nature of the instrument.