Well, it's a neck-wrap, and a balaclava, and a headband, sweatband, pony-tail holder, and more.
My favorite thing it does, and why I bought it, is for the neckband/scarf. You can see me wearing it above on our hike to Mima Falls. I had used a scarf for snowshoeing and got frustrated at the ends constantly flapping around. I needed something to keep my neck warm but not annoy me.
A friend of mine had bought a Buff for snowshoeing, mostly because he couldn't find the other two or three he already owned. I greatly envied it so before my next hike, I researched them.
I'd decided I wanted a wool one because I anticipate using it mostly when it's cold. I've never wanted something like this in warmer weather, even though people do use them in all weather. The company makes an Original Buff, High UV Protection Buff, UV Insect Shield Buff, Wool Buff, Polar Reversible Buff, and a Windproof Buff.
I love my wool one; I don't think it's itchy and neither do any of the reviews I read. I'd debated getting the Polar Reversible Buff, but decided that I didn't need that level of warmth. And I debated getting the Original Buff too, but wanted a little bit more warmth than that. It was a great purchase, and I'd recommend getting one. If I get another I might try the Original Buff.
So the answer to "Should you get a Buff?" If you're wanting something to keep your neck warm, or do so many other things, it's "yes."