I consider outlines to be MAGICAL, especially if you want to write an intricately plotted mystery or political story where all the threads connect at the end to be a huge payoff!
I also use outlines to sketch out promising story plots as very brief outlines. Outlining really is a great way to flesh out an initial concept without having to commit too hard to it... and even better, if an outline really works, you can flesh it out further to make a "skeleton" for your story that you can then drape flesh (i.e., actual scenes/words) on!
Outlines are magic and make the writing process so much easier -- and really help you figure out where you story is going.
I always use outlines for everything I write - whether it's Save the Villainess, The Villainess Wants Her Prince to Live, or even short-stories - because it really helps me keep my plot on track and gives me character arcs to write toward. Plus, since I primarily write romantic mysteries, outlining helps me make sure I embed the right clues in the right scenes to make a mystery consistent... and it helps me keep continuously developing the main couple's relationship as well!
There's a really useful book called "The Ten Day Outline" that I like and that goes into the outlining process in really great, pragmatic detail. If you're interested in outlining, I suggest giving that book a read! 