Also good to make sure you're compatible with the person you're planning to spend the rest of your life with

Hugely. I'm in a relatively new relationship, and it has been so refreshing to be experienced enough in both love and sex to know and communicate what I want and need.

Though I think the biggest boon from having some experience under my belt is that I have been able to internalise that different people like different things. It sounds like a no-brainer, but it's hard when we're inundated with rhetoric that fosters the idea of "sexual skill" as being some objective thing, as if there is, for instance, an objectively optimal way to move your tongue when going down on someone. People talk about good sex vs bad sex as if it's a simple sliding scale, but framing it this way erases so many of the qualitative aspects of sex (and the joy of getting to know a person's preferences)

I always knew that proactive communication was by far the most important sexual skill, but it's only through having experienced sex with a variety of people that I was able to properly understand this notion.