Woven wraps (also sometimes referred to as "wraparound carriers") are long pieces of fabric, usually 26-30" wide with finished edges and often cut with tapered ends. They are woven specifically for babywearing, with thick threads and a wide, open weave, which makes them very comfortable; due to the way they're woven, they have a "give" to them that is harder to find in standard fabrics. Because of the special weaving processes and materials used, and the fact that they are usually imported from Europe, their prices are significantly higher per yard, but they are appropriate for long-term wearing, from newborns through preschoolers, and many wearers find them more supportive than standard fabrics. They also offer more patterns and colors than most off-the-rack fabrics. However, if they are outside your budget, please rest assured I have put a great deal of thought and time into my standard fabrics, and believe they are more than adequate for babywearing; a slingified wrap is hardly a necessity for comfortable, safe babywearing.
Did you know that sleeping baby productions was the first company to offer wraps turned into slings? I actually coined the term "slingify/slingified" in 2005, after a customer sent me a wrap to turn into a sling, and have been offering the option ever since. Now most wrap manufacturers also sell ring slings, and other vendors do conversions, too -- but now you know the rest of the story.