Spline Meshes. Best creation? and why am I getting "pinching"

Hey everyone,
I am creating a scene and decided I needed some electric cords and such in the room.
Well I thought “Hey Splines to the rescue” maybe a better way than to try to just create a static mesh that can’t be moved or changed.
So… I search the Interweb and while there are a few tutorials on “how” to set up a spline mesh, there is nothing on the actual creation and “why” a spline mesh works (welds? together)
Are there any deep dark secrets? I.E. Open edges opposed to closed? Length? Poly count? The content example, seems to be just a regular mesh. How could I just attach a “plug or cable end” so that it doesn’t get used along the spline or spline nodes?
Now as to the “pinching”
I have just used a cylinder as my spline mesh. But I notice that I keep getting “pinching” ==><== At node points. I can get rid of them is I tweak the control points, but I’m not at any extreme bending or such (but maybe I am, as I can get rid of them tweaking the rotate controls). I tried this with a high poly version and low poly, and the same issue.
Anyway, I’m loving the spline approach (and assuming that it’s more efficient using a spline mesh as an instance along the spline than creating a static mesh?

Hope to get a few answers, and hope to help along the way,

James