A lot of people actually share this concern and you are right if you're planning on keeping what's written. I personally use it for practicing coding interview questions and brainstorming.
The 4x8 sheets of melamine backer board is cheap, cheap, cheap! Where I currently work, we have 80 linear feet of the stuff on our walls in our dev area (held up with nails and construction adhesive). It isn't fancy, but my employer believes more in results than being "impressive" (plus, we don't get any clients back here anyhow).