'Edit Parameters' simply allows you to change a feature parameter and then force an update of the model. However, you may not actually be able to see what the impact of that change might be since it could be related to a feature way-back in the history tree. However, when using 'Edit with Rollback', before you edit that feature parameter, the system 'rolls-back' the model to the place it was when that feature was originally created. Often this helps people have a better understanding of what the effect of your changes might have on the final model if you can see what it was like when that feature was first added to the model. This is of particular value if you weren't the original designer of the part (or it has just been too long for you to remember what it was that you did). While the results are generally the same, for many people this ability to see a feature the way it was at its 'birth' often helps them to better understand the changes that are being made and for some it could help get the result their looking for quicker without as much 'trail & error'.
Excellent details.i understand it is the design intent that is captured here. Let me check it out and get back if required. Thanks a lot John for your insights.