I think it's a mathematics question.
If you shop around and buy in lots, you can get air-tites for 0.30 - 0.40 each. 2x2's cost me 0.03 - 0.04 a piece.
I have a few coins that have lived in several different 2x2's. It really would have cost me almost the same to have put them in an air-tite from the beginning and be done with it.
Now if you put a coin in a 2x2 and never change it's clothing, than there is no economic argument.
Another factor is if you have kids and like to show your coins off. In that case, you can let almost anyone play with the air-tite all day long whereas a coin in a 2x2 could get damaged by an energetic 8-year old.
If I have an "interesting" coin that I know I'm gonna want to handle, I immediately put it in an air-tite to protect the coin from me.