For me, it’s exactly for “such complex things”, although I don’t consider a TV cabinet made up of simple cubes very complex As I work and add things, all I need to do is make sure UV face is collapsed and put approx in the right location in UV space to orient it. No need for any real unwrap, no need to check rotations, no need to fight to keep the scales right, no stencil painting, no issues due to stretching - fully automatic except the actual node setup. When you’re done, basic unwrap and bake out the result if you want. If you need other stuff like grunge or decals, you can always do appropriate unwraps for those purposes.
What I can’t do, which annoys me, is use triplanar this way on simple planes with a solidify modifier for truly nondestructive modeling, as the UV face needs to be assigned a location in UV space to behave as desired.
I think LordOdins approach may be suitable if you want to use armature or curve modifier to bend things into shape. Box mapping will follow the shape, but controlling scale stretch becomes difficult, probably sometimes impossible. This because it uses generated coords rather than object coords which you want for scale control or externally referenced orientations.