Depends why you build. You seem to suggest it is about gaining skills and challenge for you, which is fine. Somewhat the same for me. For others it is about getting th job done at a high level and fast enough to keep in business. What if you came up with a way of making better frames than anyone else, but it was too easy, would you use it?

Jigs mean a lot of different things. Some of the better jigs are multifunctiona and will allow you to build without subsequent cold setting, or minimal setting. They can't hold the frame against massive forces that would move the joints around, but if the correct sequence is followed they can reduce the post forming to a minimum. They can also be pretty useful at getting parts through the process.