To this day, I think JS had a pretty strong sexual appetite, and was attracted to young girls. He had to justify his indiscretions, and hence, plural marriage was born. I know only the righteous could practice it, but there is the Fannie Alger story and you can see how pedophile-oriented people in splinter religions use it to justify sex with multiple women and young girls.
Ironically, my wife likes the idea of plural marriage. She doesn’t like housework and sees it as a way of easing the burden of running a home. I would be uncomfortable with it. I would rather have a solid, loving, engaging relationship with one woman and leave it at that. Managing more than one would be difficult.