Sheer shades can be formal or informal. They look very nice and fit well in both situations. They will also pull out of the way. They roll up inside a headrail and will never take more then 3 1/2" of space when rolled up. Unlike some of the name brand competition, you can actually lift the blind in a semi-opened position. This can give a cool glowing look to your area without having to have the blind pulled all the way down.
For ALL roller blinds (sheers, roller shades, sunscreens or any blind that rolls up), the fabric is narrower than the roller. It has to be this way to make room for the mechanisms that operate the blind and the fabric.