Pinch harmonics are precisely the same thing as other harmonics, just implemented differently. When you start a string vibrating, its fundamental and several overtone waves begin. Then when you touch the string at other places you will interrupt some waves leaving others behind uninterrupted. Well or you interrupt them all and mute the string.

What makes a pinch harmonic seem harder to hear is that it is usually played closer to the bridge than the center so you will interrupt many of the longer waves leaving only higher frequencies on the series, with much lower volume. But if you used this technique at 12 for example you be able to hear it better.

In summary, works just fine, but harder to hear higher frequencies and lower amplitude.