The lie angle must deviate by 10 degrees from vertical, good for Bryson for noticing. The more vertical the stroke ( a shaft plane deviation of only 10 degrees) the more margin for error. Why haven’t the putter companies featured more models with that shaft angle? Coupled with the arm lock Bryson has created a style with few angles and moving parts. I’m sure he has put a lot of hours in grooving it; in the last few weeks his putting seems to outshine his driving. He probably noticed a lot of long putters have a shaft angle of 80 degrees, he was rewarded for his creativity.