It really comes down to whether or not you'll appreciate and ride another bike if you build it. You could build and flip but there's always something you'll need that will cost $ to complete the project. If collecting another bike has no interest, it's probably best to sell the components.

After my first vintage build I thought I was done. I quickly realized I wanted another and had a clear case of the N+1 bug. Very happy I hadn't sold off all my spare pieces.