I think kicking off in OT is optimal play in an outdoor stadium. I'd rather the advantage of the wind then the advantage of first ball.
Going into the game kicking team has gone 32-32 since new OT rules were put in (32-33 now). So it's not like there's evidence as to which is better one way or the other.
You did it. You figured it out. It was a lack of trust in his star quarterback, rather than caution regarding the absence of a functional offensive line along with injuries to the team's three best receivers aside from Gronk, that caused BB to defer.