The above two posts are valuable in that they both touch on what may be useful points. Bi-wiring, for example, with at least some Vandersteen speakers (e.g. 2CE), apparently allows the user to make tonal changes via dials on the back of the speaker. In other words, the speaker is designed to be bi-wired, and to allow the user to adjust the midrange and tweeter levels.
Assuming that the two features are not distinct (i.e. completely separate), then of course the combination will allow the user to change the sound. Considering that to be an advantage is one thing, but to argue that bi-wiring alone improves sound is another.
With regard to @hshifi's point that bi-wiring allows the user to "tune" the wires is similar. That would be very different from the claim that a simple bi-wire setup is somehow superior to a single cable. Simply adding "more" cable is not in any way supportive of bi-wire being superior, and for what should be obvious reasons.
Assuming that the two features are not distinct (i.e. completely separate), then of course the combination will allow the user to change the sound. Considering that to be an advantage is one thing, but to argue that bi-wiring alone improves sound is another.
With regard to @hshifi's point that bi-wiring allows the user to "tune" the wires is similar. That would be very different from the claim that a simple bi-wire setup is somehow superior to a single cable. Simply adding "more" cable is not in any way supportive of bi-wire being superior, and for what should be obvious reasons.