The only advantage to a BIAS WWM is the length/comfort. It's hard to make a recommendation without your size, but I'd suggest that if you're below 5'9, the Nano would be perfectly adequate. It "retails" at 7 oz., but that includes suspension hooks or biners (can't recall which). Without those, you're in the 5 oz. range. The WWM is 6 oz. but comes without any rigging other than channel loops and a fixed ridgeline. A suspension kit including stock straps, whoopies and toggles runs about 4 oz. Bear in mind the Nano would still need suspension.
I am not trying to sell you but explain the differences. Our WWM was inspired by a desire to create something lighter and more comfortable than the Nano. But some folks don't need "more comfortable" because the Nano is adequate. Some folks say it's lighter because stripped down, it can weigh less than the WWM (but it's four inches narrower and two feet shorter, so that's basically why). This is a comfort tradeoff for bigger folks, but smaller frames won't feel it as much... other than the bigger hammock will swallow them.
Hope this helps. Thanks again.