As per Google maps, it takes the same half hour -32 minutes vs 33- walking or taking the bus from Banqiao station to NIA New Taipei City.
It says 10 minutes by car …if Loreto from Fast and Furious is driving, perhaps.
Please notice we are leaving out the fact that if you are coming from Tamsui, you must transfer to the blue line to get to Banqiao. That alone adds about an hour. At least.
How about if you are coming from say, Pinglin? Shiding? Ruifang? You realize it is all New Taipei?
Why the heck don’t they have a small NIA at each district office is beyond me.
So OP’s move to go to Keelung site is beyond brilliant.