2-channel amps with 4 sets of binding posts

Why do some 2-channels have 2 sets of connectors for each channel? Thanks for any insights.
Maybe for bi-wiring, or they might have an A/B speaker select
several amps provide connections like this for the speakers. It is indeed for bi-wiring.
I have the White Audio Labs---(Big Mutha)It has the 2 sets per side for biwiring.
Some Linn amps, the Klout and others, have 3 pair per channel to tri-wire a speaker. Just about any high quality
amp on the market has two pair per channel.