With TIG the jigs are often better, and the joints are often better. It's a different culture. With lugs, you can often get a dead nuts set up on a joint with a pass through of the tube. With TIG they are basically all butt joints, and ideally they would be perfect, which is easy to achieve with an industrial level set-up (or due care with a file). With TIG some welds will require a root pass, and a filler pass, others can just be tacked and welded. You have to be very tactical on how you tack the tubes to minimize distortion but build enough strength into the tack, but not make it unsightly when you weld through it on the run. I haven't done much welding recently, but I did a utility table where I had to weld some 1/4 wall tubing to a quarter inch plate, and I used a tiny stick unit, and made some small welds off 110 in the wall. I got a little overprottective and ended up bending the plate like a banana, I just never thought that would happen with the scale of the welder and the plates. The forces are considerable, even when they aren't matched to walls 1/10th the thickness. In fact bike fillets from TIG are way oversize, so the people that are good at this are running huge fillets on tiny thin walls, and turning out straight work.

Scooper's sequence still leaves a lot up to the skill of the operator. Guys that can do perfect lugs or brazing jobs, with minimal clean up and minimal distortion, that is lots of experience at play, and huge skill on display.