Hi Presonus team,
The idea of feature is the following: output of a track/bus is cached when being played for the first time. Then, if there are no changes to track/bus/bus sources/plugin side chains, cache is used for following playbacks instead of real time re-rendering thus reducing CPU time necessary for rendering this part of signal path. If there's a change, cache is updated during next playback.
When we mix in Studio One we usually focus on 1% or less of a signal path at a time. Re-rendering the other untouched 99% in real time seems completely redundant and at some point it becomes limiting. If this feature is implemented, users will be able to focus more on work and be less disturbed with CPU load and necessity of taking track freezing decisions or actions.
I'd also suggest that auto freeze is a switchable option to let users turn it off if they want to.