Why do some curves have NO CURVE!

Hi folks,

I’m still struggling somewhat with curves!

Please check the vid below.

I create a mesh circle

I convert it to a curve

I go into edit mode and drag some curves around

What i don’t understand is, why isn’t my curve being rounded out, like in the screen grab also below?

When one converts a mesh to curve, is there a way to choose what kind of curve it is? (Bezier or Nurbs?)

And can you convert a Bezier to Nurbs or vica versa?

Thanks in advance!

Haha, i solved it myself two minutes later!

The trick is, after you’ve gone into curve edit move (at 0:21 in my vid), do:
curve > set spline type… and there you can choose nurbs, bezier, or poly (no idea what poly is useful for).