A Field Programmable Gate Array (FPGA) can be reprogrammed into doing almost anything you want it to do. If the printed circuit board around it doesn't support your new application, you can still re-use the FPGA.

An Application Specific Integrated Circuit (ASIC) is locked into doing only one thing. It's not field programmable.

So yeah, an FPGA miner probably has higher reuse value than an ASIC.