If your 2d maps show where walls, cover, and difficult terrain are, the go for it. D&D Miniatures and Heroclix both had good fold-up poster maps perfect for this kind of game. There are also a lot of excellent 2d resources at drivethrurpg.com and related sites. In a pinch, you could simply use a marker on a piece of poster board. As long as you and your opponent know what and where the terrain is, there should be no problem.
With that said, part of the fun of miniatures wargaming is the pageantry of fully painted miniatures on a completely developed 3d world. So while 2d can get you up and running faster, it really is more satisfying with 3d terrain. If you like papercrafting, there is a huge amount of free, easy to assemble terrain template PDFs out there. Just print them, assemble them, and you can have a beautiful game boatd in no time.