It's worth taking the time to observe ecological interactions with 'weeds'.
All the literature claims that weeds aren't a food-source for Australian native animals and that they routinely displace native plant species.
However if you sit and watch, you can see throngs of native animals eating the weeds, even preferring them to other foods and the displacement of ecosystems nearly always has human activity undermining the stability of established systems.
When plants crisscrossed the globe thousands of years ago, we call them 'naturalized' and they can become an integral part of ecosystems.
(Thinking of Nymphaea caerulea)
The other thing to note is that the global temperature is rising and the migration patterns of seed-carrying birds has been altered.
What was once an opportunistic tropical weed outside its natural range, brought by humans - is now a natural pioneer, brought by birds and germinated at optimal temperatures, providing food for subsequent generations on their now altered migration route.
(E.g. Schefflera actinophylla - umbrella tree)
I'm a fan of Lawton's term 'fast-tracked carbon pathways' as the weeds are often ready to become mulch before your green manure crop is three inches tall.
Weeds are often 30:1 ideal composters, which makes them chop n drop gold.
Weeds are usually very high in trace minerals, which is vital for soil biology.
Weeds like Paddys Lucerne have extremely high leaf-protein content, making them ideal forage for animals (or making a veggie soup more hearty).
There are 7 billion humans rearing 20 billion chickens, cultivating a trillion kilograms each of corn and rice, spending $30 billion on carcinogenic herbicides.
Every. Single. Year.
The real weeds are us and the fruits of our labours. Occupying every niche and displacing the wildlife.
The so-called 'weeds' are trying to clean up our mess and they are full of the food, fibre and medicine we could use to decarbonise our hubristic lifestyles that are fueled by outsourced environmental destruction.