If I see an item for which the BIN price is WAY more than I think the item will likely fetch and/or I am willing to pay, then I stomp the bin by making a bid, and then enter my snipe through AS, as usual.
However, if the BIN is reasonable, and certainly only a few dollars above the bid, then I use BIN.
For me the acquisition is the objective and that is usually achieved by taking advantage of the BIN.