fuel pump

[cali201]

Question: When I bought my '68 AMX a few months ago it came with an afermarket fuel pump (electric) in the trunk. I put in a cut off switch to the pump as a security device. One day I forgot to turn it on and drove off--that was 2+ months ago and it is still running. The original fuel pump (manual) is still in place and apparently working fine. Why would the prior owner have installed the electric pump if the original works fine? Is there a performance advantage with both pumps working at the same time?

Thanks for any insight to this