"""""""Good lesson there: use Show pts to check the curves *first*."""""""\

Not really "show points" as that wouldnt really show you what you are looking for. What you are looking for are "Seam edges" that when modeling later, if you try cuts that intersectin and out and skim at very small values, will make it hard to work on your model..

So, if you just extrude what should/could be a single contiguous curve and the surface has a seam in it, then you can find these easier...And rebuild them.

The other thing to note about rebuilding curves though, is that you want to look closely as too open of a tolerance will actually be changing the curve! ALso, a downfall and reson NOT to rebuild all the curves, is you will be making a light curve, with maybe 5 points in it, contain possibly hundreds of points!! Which makes the surface heavier, and can compound the model to be unnecessarily heavy..

Use it where you NEED, but not overdone on everything! IMO