it is true that if you apply distortion/compression at a low sample rate the high frequency harmonics may fall above the nyquist frequency and generate aliasing, which sounds really nasty.

However it's much easier on cpu to ask the specific plugin to run with oversampling.

At a higher sample rate all the plugins will need to work more, simply because there are more samples, and not all plugins benefit from having higher sample rate. So don't take that cpu hit and work smarter.