now that's funny
I never have used chemicals IN the garden, now We live out where every weed seed known to man blows in from the vast farm fields surrounding Us, hence, we get alot of weeds, primarily Canadian thistle, burdock, lambs quarter, and pig weed...
IN the garden, all that appear are Hoe Hoe Hoe'd...and composted.
(some of the young lamb's quarters end up in my salad bowl)
Weeds have much deeper and far ranging root systems than garden plants and bring up many nutrients NOT available to your garden plants...which contributes to your compost.
That being said...I too have in the past used roundup, NOT in or even near the garden
..I try to keep the large stands of burdock down around the perimeter of the yard, because they sure mess up your pets fur...
The Un-sprayed Burdock sometime gets dug for the roots, Which I brew into tea for my health
and the thistle hurt your bare feet...However...the birds like the seed, so some, not all (to farmers dismay) is saved in an area
So I chop, hoe and mow for the most part...but there is times and areas that a little roundup is used, with care, and scrutiny