That information could absolutely play to Jon’s favor should the Night King find his way into the Great War.
Either way, knowing something is a huge plus for he who used to know nothing, going into Season 7.
It’s also possible Jon could share his knowledge on defeating the wights with one of his present enemies, in an attempt to win favor and/or enlist all the help possible in the upcoming White Walker battle.
Best case scenario: a wight invasion wipes out the clueless Dothraki, Unsullied, and Southern Bannermen, while the Northerners limit casualties to a minimum using dragonglass daggers.