In some particular situations you want to place a loop cut between two existing loops without giving a distortion to the final subdivided geometry. In earlier version of Blender it was possible through CTRL+R then S(smooth). IDK why devs removed this incredible feature through tapping S key, but sometimes you really need this. If someone knows how to do this, please reply. Thank you.
P.S. I roughly searched modelling forum thread but I didn’t find an answer. Sorry if I’m being neglectful if so.
The only thing I found is when you select particular edges or edge rings you want to place loop/cut between is that u can do specials (W) and select Subdivide smooth.