Can also use my curve sweeper (Sorry to always be plugging this but it’s pretty cool and everyone should use it (you can also use it make curve-clumps in 3.0 without the copy object node!)). It has outputs dedicated to those and you have the option to sweep the profile as points, which produces singular curves:
When not using points as profile, it uses the method described by @HooglyBoogly to make line-meshes.
Good luck.