From my experience, to put it simply, sometimes it may be just a tad bit easier to explain things (especially if you're into teaching or just wanting to share the inspiration behind certain licks).
I've been self-taught for 11 years and only recently got myself attached to a guitar teacher with 5 decades of experience in playing and teaching, and when I played out all the Synyster stuff to him, and he was able to break down what scale or modes were used here and there (he even put Syn in his list of intelligent guitarists eversince i showed it to him). I've had trouble explaining to people what I play (technique, especially) prior.
I wanted to venture into teaching as well, and being self-taught, it was almost impossible to teach someone else without saying "just play what you like and pick it up by ear" or "okay so it goes like this, then like this, then take this finger and do this" because not everybody has the patience to do so hahaha. So I had to find a way to break down my process of learning and playing, and that is by going back to the basic syllabus, and only then, I was able to explain whatever I've been playing the past 11 years, properly, to other people who were keen to learn what I've been doing.
It's not compulsory, but yes, it's a good knowledge to have, especially when, for example, a set of arpeggios transit to another, makes a lot more sense than just 'random noodling'. Noodling works, but it helps to just make the notes sing a bit better to ensure you're not seen or heard as tone deaf or disrespecting the music vocabulary. Makes you sound a bit more professional and convincing too instead of the "just play it out man" way.
It's a vast world of music out there. It's beautiful.
Cheers! 
