Is Standard Deviation more important than average BG or Time-In-Range?


Well, as you have pointed out there are two issues at play.
#1 - What is my range to try to maintain. If you choose a range of 50-300, you would have a TIR of 100%, but if you choose 70-80 (obviously absurd) then you would have a very low TIR. What you set your range to has a lot of influence.

#2 - Is my method of measurement accurate? Well thankfully for us the Dexcom is mostly accurate most of the time, so a TIR has more meaning to us than to someone for whom the technology doesn’t work as well.

Without having a well thought out range, and a measurement system that works for you most if not all of the time, then the TIR isn’t all that helpful.