Never have experience with bi-wiring as all my speakers in the past is single wiring configuration.
Why speakers makers make bi post anyway? Any benefits?
In theory, this allows reduced interaction between the bass and high frequency units. Apart from the benefits of tuning using separate cables already mentioned by jb, you can also bi-amp, i.e. use separate amplifiers for the high frequency and low frequency units.
I asked a very prominent designer once on his thoughts on bi-wiring (his speakers use bi-wiring terminals). His answer was interesting ... he said he provides this because this is demanded by the market, not because of any technical benefits.
On a good day, bi-wiring brings about gains in transparency, and separation. On a bad day, the two drive units end up sounding disjointed and uncoherent. This results seems to me to be quite speaker dependent.