Do you only get them if you have trouble sleeping? Or is there something I'm missing? Do you use one and why?

I never got one with my first but considering it this time (18 weeks now). I'm sleeping ok - typically a stomach and side sleeper and stomach isn't uncomfortable yet. Am I missing some other benefit though? Besides that they look super cozy and indulgent ☺️but I am also the type of person that only buys things I'll use for years and years, so having a hard time committing!