In the past the syllabi for MusicTheory courses were rather classically orientated so unless you wished to learn about Bach's machinations you might well be put off.
Not so anymore.
There are now Popular MusicTheory courses available which are somewhat more attuned to the rock, pop and blues enthusiast.
These are very handy for assisting you in learning tunes fast and understanding what's going on generally, leading to considerably less anxiety when performing.
LCM Popular Music Theory graded workbooks.
Quite naturally most students want to get stuck in, start playing their favourite tunes and be free without having to be burdened by the necessity of learning some esoteric sign language which appears to be more of an impediment to this quest than an aid.
In fact I recommend this approach because...
...it's once you're up and running that the use of knowledge of these areas will become apparent to you.
You can avoid the issue of the entire sound of your band changing if a key member is replaced, which can happen if you don't know what they'd been up to.
You can capture and understand your ideas and those of the artistes you admire more readily.
It's becomes much easier to remember tunes in terms of keys, chord patterns and structure than individual notes on the fretboard.
You'll be able to write and follow chord charts and to transcribe your favourite solo's.
It'll aid your songwriting and compostion.
You'll be able to replicate your performances to the highest standard.
You'll be less concerned about making mistakes because you'll be able to recover effortlessly.
Music colleges demand that students know this stuff for they can not communicate with them otherwise so knowledge of it opens new possibilities.