There are some cases u will come across where a 3d solid might not be the right option.
There are some scenarios where using ruled surfaces or edged surfaces is the better alternative - just depending on the modeling method and what end-result you are going for.
You can check out a thread a while back where I modeled an F-16c using only ruled surfaces with varying surftab counts.
Loft command would work to a degree but a mesh perfectly depicted the fine smoothness I was going for.
-ChriS