Can depend on the sellers you are looking at now. Some sellers use Second Chance Offer alot - some never use it.
As heidilynn0_3 said, a seller may have more than one of an item. And using Second Chance is a great way to sell those items quickly and easily. If the bids below the winner are still within amount the seller is happy to sell for, then s/he can offer a Second Chance and (hopefully) get the items sold almost immediately without going to the time and effort of relisting.
Of course, it IS always possible that the scenario is sometimes as you suspect. So, your call. If you want the item and were willing to pay your bid price, then accept the Second Chance. If you don't like the deal, or would rather wait and look elsewhere or see if it comes up again, then ignore or turn down the offer. You are in control.