I use the process used by Lisa on YouTube (I Dream in Soap) and love it! If you use fine Himalayan salt, the soap is not too scratchy at all. My customers can’t get enough of it. I do not find it necessary to cure my salt bars longer than my other soaps.
I am just relating my own experience, and this is the difference in the lather from my salt bars. The first bar is 7 months old and the second is 5 weeks.
Below is a bar from the same batch as the 5 week old bar above, after curing for about 2 years. So in my experience the longer cure time is important. If you get the results you want after a normal cure time, that's great!