Thank you ladies for your opinions. Yes the term "weed" is relative. One has to pick one's battles.
My lawn is mostly weeds. One section is wild thyme. I love mowing there.
I live along a creek. The thicket can be beautiful with wild flowers, dull or nasty. I would like to add the Smartweed to the more dull unidimensional areas.
Would this "invasive" weed squeeze out lets say garlic mustard? Because garlic mustard is sapping my ferns nutrition and they are not growing as tall.