The RAW remains the most important file from a session. Beside it, though, a small .set file can record how that photograph was developed in Acutance Studio: exposure, white balance, curves and other adjustments. It does not replace the negative. It accompanies the work.
Keeping choices in a sidecar has a practical consequence: the RAW need not be rewritten whenever you change your interpretation. You can try an HDR rendition, return to SDR, reconsider the crop or level the horizon without accumulating a chain of intermediate JPEGs.
The relationship between Studio and Photo-View becomes more useful when those files travel together. Photo-View can recognise a .set and display the established edit before you export. During a client selection or a review of hundreds of frames, that avoids preparing a JPEG for every trial.
When you archive or move a folder, keep the .set files alongside the RAWs. Back up both. A final JPEG is convenient for delivering the photograph; the RAW and sidecar are what let you resume work months later. It is a small habit that protects many creative decisions.