I'm more comfortable with the path syntax, and polygons are pretty much the same as a path, except that you would prepend M and append z to the list of points (for certain buggy renderers it might be necessary to put an L inside, too). Paths have handy shorthands for horizontal, vertical and relative movement, though.
If you're more comfortable with it, that's great. To someone who's not already comfortable with it, points="0,10 20,10 10,0" is a lot more obvious than d='M0,20h20L10,0'
