Can you prove that there are NOT obvious advantages to being a warmer? I've played the game. There is a reason why there are heated benches, mittens, face covering warm weather masks, overcoats, and hand warmers made for players - it is better to be comfortably warm than uncomfortably cold when playing football. Otherwise there would be no need for all the gear the players wear in cold weather. Prove that it isn't better to be comfortably warm than it is uncomfortably cold, and prove that it isn't warmer in the sun than it is in the shade. Hint: it is warmer in the sun.
I say all this as a ticket holder on the home side, which I love. In general, there are as many or more games during the year where the north side is uncomfortably hot in the sun as there are games where it is more comfortable in the sun, late season.
I totally get why they put this provision in and in rare instances (a sunny but frigid day in November with an 11:00 AM kickoff) where it is better, I'm glad the team has the option to move sidelines.
It didn't take the Vikings long to make the exact same decision, because they didn't just have cold games in November. The NFL played on into January. I say the Vikings made the right decision as well.