Instead of imagining performing music as a series of notes coming at you, A C G B A, imagine it as a series of motions: A-C, C-G, G-B, B-A. The purpose of a technical exercise like a scale is to put those motions into your muscle memory, so your conscious mind is no longer thinking about them. Scales should not be the only exercises you do; I do not play guitar, but a piano player should certainly also do arpeggios, circle-of-fifths, "circle of thirds" (rolling up major and minor scales by thirds, also going up and down the keyboard in pure major and minor thirds. there's also some good multi-finger exercises you should do to, like scales+fifths, and some genres really call for yet other technical exercises). I don't know what the guitar equivalents would be but I am sure there are some.
Unfortunately, the only way to put something into muscle memory is with repetition... endless, endless repetition. Alas. (No sarcasm.)
It is absolutely true that you can play without this, but instead of a powerful set of abstractions stuck in your muscle memory, you will have a patchy set of whatever you happened to need. Which, on average, due to the uneven need for them, will indeed correspond to most of what you need. But you will have holes compared to someone who is doing the full set, and the further you try to go the more those holes will bite you.
I say this without judgment. Far be it from me to condemn somebody for learning an instrument and choosing not to devote the time to become an utterly awesome expert. I think it's a perfectly viable choice to choose to become pretty decent. But you should know what you are doing.
It is not at all like needing to know Turing Machines to know how to program. It is much more like (though not identical to) needing to know how to type fluently to program; if you're hunting around for the open parenthesis, you're not programming. This metaphor breaks down because your editor will wait for you to find the key, at worst it breaks your flow; when playing music if you come up against a missing muscle routine you just failed something.
(Incidentally, when I put it this way it seems obvious, but for all the music training I've had and for all the various instruments I've learned or at least poked at, nobody has ever put it this way to me. It's too easy to insist that it's simply tradition, or to start babbling about some semi-mystical thing or other, when really it's quite simple: you can't play at a high level, or even a middling level, with your conscious mind. The vast bulk of your instrument-playing routines need to live in the cerebellum. It's that simple. It's not merely because it's tradition and there are concrete and simple reasons why technical exercises are necessary, appeals to authority are unnecessary.)