For example, on guitar I am playing through triads in the same position through a chord progression and obviously this is voice leading as exactly the same notes are being reused regularly and so often a chord change is almost indiscernible.
It's not really obvious unless you give some more detail, ideally notation of some kind. But I don't think we need to know what you're playing to answer.
Voice leading just means to move voices, or parts, to move them melodically. Technically, if you move voices any way it would be voice leading, because the voices moved. "Good" voice leading is usually meant to describe the counterpoint conventions of the Renaissance, Baroque and Classical periods. In a nutshell, it's triadic harmony, hold one or two voices, move the others by step, no parallel perfect fifths and octaves.
To literally not voice lead would be harmonically all voices singing a unison or a static chord. To move the voices, but without the independence of parts achieved with "good" voice leading will be parallelism. That is found in a variety of styles: organum, folk music, Impressionism (like composer Debussy), Modernism (like composer Bartok), or rock music.
Why, do some styles not use "good" voice leading? Some possible reasons:
- To deliberately not sound like Renaissance, Baroque, or Classical style, especially the "learned" or Church styles, which is the actual origin of the voice leading, contrapuntal methods. If you don't want to sound like you're playing a hymn, avoiding "good" voice leading is one way to do it.
- To "thicken" the texture of a line. Sometimes, even in the context of a symphony, the texture can change to unisons or octaves for a passage, such passages can be thickened, for example, by playing in thirds, if the style were modern, doublings in fourth, fifth, sevens, etc. might be used. Harmonically the passage will be thicker with multiple parts, but it won't involve voice leading.
- From a linear point of view you might try to make a line more emphatic by moving everything in the same direction. When various parts move by contrary or oblique motion, you could think of that are parts sort of "contradicting" one another by not moving in the same direction. Of course that variety of directions is what creates the special texture of the contrapuntal style. But it is a sort of constant churning of various directions. If you move all parts in the same direction, it would be considered ham-fisted voice leading by conventional standards, but it would give an emphatic, single direction to a line.
There is a particular type of movement that I think should be pointed out: moving across the various positions of a chord. Technically, it isn't quite parallelism. It's similar motion, but the important thing is a single chord is maintained. Debussy did it a lot in the Impressionistic style. You can also hear an example of it in the vocal harmonies of the Beatles song Because. In terms of conventional voice leading all the parts move in one locked direction, but harmonically it's a very rich sound.