AFR meters are great for tuning but as with many diagnostic tools you have to know what to do with the information. Does the AFR reading line up with the drivability issue, exhaust smell, plug condition, etc?
I’ve been using mine along with other tools/methods for over 5 years of progressively going faster at the strip, cleaning up gas stench, better response and transitions from idle up to wot. With any upgrades/changes to my engine I have to tweak the tuning. I don’t fixate on any specific reading or adhere to absolutes with tuning each circuit. More focused on a range. So I get in the range then fine tune further sometimes using the above additional methods and the final numbers are what they are. I know some prefer reading plugs and are quite sharp at it, it’s a lost art I’d say but it is possible to do the same with the afr gauge “along with incorporating some of/even all the other methods” to get it done much quicker.