They scrunch up into some odd shapes, and likely the flour will have to be sifted before use, but it works.
As always, store at a constant, and preferably cool temperature, and out of the sun. (I know you know this, but not everyone reading this thread might.)
The only drawback to the bags is that critters (rodents, especially) can ruin them fairly easily, so store the bagged stuff in a metal container (like those big popcorn tins you see this time of year) to keep them undamaged and in the dark.
The food saver bags are good, but they will eventually ‘breath’ and allow air in that’s why I use the canning jars and/or Mylar bags.