Learning your scales is just one way to get from being a beginner, to becoming one who can play a wailin' Jerry solo without "Clam-ing out" all over the place (Clam = blatently wrong note(s)).
Practicing your scales builds muscle memory (the connection between you brain and your right/left hands/fingers) which will, again, help to keep you from Clamming out during a solo (if you play the right note, but pick the wrong string (or mis-pick the correct string), or put your finger too close to the fret, for example, and it comes out sounding like... a clam).
You can also use scales a means to practice adding 'vibrato' to every note.
You can also use scales to practice ascending/descending tripolets "do-re-me-do, re-me-fa-re, etc...), which can be commonly heard in Jerry G style.
Now the way I did it, is to learn a few box patterns that you can use on any song, play those for 30 years, then get so bored stiff, you finally decide you want to unlock the key to solo'ing, and you go back to square one and learn your scales.