Technique is what is known in philosophical circles as an "instrumental good", i.e. something good only as a means to a true good, an "intrinsic good". For example, money has no intrinsic worth, but only value as a means to an end. Some philosophers think that the only real intrinsic goods are states of consciousness like happiness, for example. So technique, in the sense of ability to play or compose, is an instrumental good. The intrinsic good it is the means to is the expression, or rather, the state of consciousness aimed at in the ideal listener.
But things are more complicated than this. Technique sometimes is mistaken for an intrinsic good. John Lennon didn't make that mistake, that is, he didn't spend the next six months working on his finger-picking technique. Instead he dumped that technique as being simply unavailable and kept searching for the true expression of "Strawberry Fields". The odd thing, of course, is that it didn't exist yet. Hunting for "Strawberry Fields" was not like hunting for mushrooms in the woods as "Strawberry Fields" was nothing more than a sketchy idea for a possible future song. But that's what composers and song-writers do...
Getting back to the point: things are complicated because you don't know exactly the end, the intrinsic good, you are aiming for. All you have is a bunch of techniques. Which may or may not be appropriate. Finger-picking wasn't an appropriate technique so Lennon dumped it. Sometimes you have this foggy idea of something and you just try out, instinctively, different techniques until something seems to click.
Sometimes you are afraid of losing the inchoate expressive idea if you get too 'technical' with it. I suppose there is another Beatles example I could choose: the Phil Spector production version of Let it Be which buries some songs in a "wall of sound".
Sometimes a limitation in technique actually helps the expression and I'm thinking of a very unusual prelude by Bach. The E flat major prelude from the Well-Tempered Clavier, Bk 1 is a justly-admired prelude, but very atypical. A lot of Bach preludes are a single-minded exploration of an idea. But this one is like an improvisation set down on paper. It begins with a toccata-like improvisation that stops and then starts again as a loose fugal improvisation that then becomes a double fugue as it weaves in material from the first improvisation. This is anything but a tightly-written fugue as the subjects are vague, unstable. As if to contrast with the looseness of the prelude, the following fugue is tightly-written. Together they are like an illustration of the idea that technique and expression are different things and a triumph of technique is not necessarily a triumph of expression. For the truth of the matter is that the prelude is more expressive, more deeply affecting than the jollier fugue that follows.
Bach was heir to the greatest dynasty in Western art. In this prelude and fugue he lets us hear the process of composition as it sketches out different possibilities and at the same time achieves a kind of expression that would not be possible in a more fulfilled form. Have a listen to see what I mean: