Paul, You say "I spotted this quick and easy way to make a dowel end: "... and, in fact, you did just the ends of those sticks...
But these jigs really shine at making
any length dowel, and
any diameter you might need. Metric dowels, sure! The exact size to fit into that pipe, awesome!
If, however, you need round tenons (for furniture-making or round
wood railing ballusters) there's this tool:
Lee Valley Tools Veritas round tenon cutters
Use a hand brace or in a power drill.
They make a nice swoopy transition between the tenon and the
native material. Looks like they would not have any hang-ups with any little knobbins or knots either.