It helps to use images to make the point. This a mountain town (which I will not embarrass by naming in this blog) where every available inch is covered in scentless chamomile:
|Scentless chamomile is a prolific seeder, and rapidly colonizes any bare ground|
|Pick a bouquet and throw it away|
Pulling weeds from roadsides or your yard is a total win-win situation -- you prevent hundreds if not thousands of seeds from going into the seed bank, and you get to enjoy free flowers! Just be sure that you limit this concept to noxious weeds, and not our native plants. Pretty noxious weeds (aka invasive ornamentals) that are good candidates for "free flowers" include: yellow toadflax, dalmatian toadflax, bouncing bet, dame's rocket, and common tansy.