The theory is that paddle strops are "harder to get wrong". IMO you don't have to start on a paddle strop but they're flat and solid so less prone to getting cuts on the edges. You could conceivably use paddle strops your whole life, I don't think it matters, but if you want to use a hanging strop, first get one like the ones Bill sells, they're well made, canvas on one side and bovine leather on the other, and won't break the bank. Plus his are 3" wide so the whole blade will fit (at least diagonally) on the width of the leather, which makes x-strokes less of a necessity, although I find that it still helps to do that so that all parts of the blade get run across the edge.
You will inevitably catch the edge at some point and put little nicks on it so don't spend big bucks on your first hanging strop. These can be fixed by trimming off any flap and sanding down gently.
At some point you may feel you're unlikely to damage your strop any more and want to treat yourself to a more expensive one, but it's not necessary to start. However do avoid the very cheap ones from no name sellers on ebay, some of them are absolute rubbish.