Unsealed meat in freezer Below is my situation:

Is completely (vacuum) sealing leftover meat in the freezer absolutely necessary? I would always just use a plastic bag to cover the meat and fold it around couple of times so it's almost as good as sealed (usually grocery plastic bag is much bigger than the piece of meat) and have never had a problem with it last a decade or so I have been cooking.

But recently I got this new roommate who insists on me using special small plastic bags with sealers to use and he is being very paranoid, obsessive about it.

So my question is: Is he right?
If you are noticing freezer burn or foreign odors/flavors with your loosely-wrapped meat, then you need to do a better job of storing it.   

Your roommate may be in this habit because he is used to storing things in the freezer for a longer period.  2-3 weeks is longer than I would store something loosely wrapped like that in order to maintain good quality.