Guitarists have frets, and therefore do not have to worry about intonation so long as they have a decent instrument and can tune it. Intonation on a fiddle is another matter, of course, and different people approach it in different ways. For myself, as an "ear" player, I feel more comfortable with the instrument close to my head, where I can best hear my voice, and a loose hold between chin (or, more accurately, jaw) and collarbone with the fiddle supported by the hand does not require any twisting to the side.