Yes, you can freeze flour and dry goods. Yes, you should freeze them if you want to keep them long term. Yes, there is a reason to do that. It's to keep any critters from hatching and eating the flour.
We'd all like to think that everything we eat has no, um, unwanted insect contents, but the fact is, flour can get mealworms eventually especially if it is in a warm, moist place (you know, like a kitchen....). Therefore, if you freeze it, it won't do that.
But you don't need to freeze these huge buckets!!!! Assuming you're buying 1-pound or 5-pound bags of flour, all you need to do is pop them in the freezer for a couple of days. Any eggs that are in there will freeze, die, and you're good to store it.
However... I gotta tell you that unless you are intending to quit your jobs, both of you, and holing up with absolutely no human contact whatsoever, you might better spend the money on Tamiflu and Relenza prescriptions just in case; then eat well, take good care of your health, get the REGULAR flu shot that is out and available now, and don't worry about a disease that does not even exist yet.
Just my $.02 from a Texas babushka