Kind of hard to spend over $300.00 for a AFR, and not use it. Even after being set up on dyno, I would still like to keep an eye on it.
Most definitely, if you are using a EFI controller that allows you to change then it definitely allows you to tweak it in for weather changes and the like. Mine is set at 13.8:1 currently. It has leaned out since it has gotten colder, but not dangerously lean.