Confusion regarding weeds

What are the problems and benefits of weeds? Do weeds take away soil nutrient from young plants? In my country it is common wisdom to keep the ground around your plant clean of weeds because otherwise they will steal the water and nutrient away from your plant. I have read 'weeds:guardians of the soil' and the message in it seems nuanced. For my part I believe weeds to be harmless unless their vigorous growth shades out your productive plants. So are some weeds in your garden bed okay?

Complicated subject. First is the whole issue of what is a weed? Then the question of which is worse for your crops and your soil, bare earth exposed to the elements, or "weeds" competing with your crops?

Some competing plants are really competition and potentially destructive. Bindweed and other climbing vines can pull down your crop plants. Not so good.
Something like a dandelion, low growing, deep taproot, not going to shade out anything more than a couple of inches tall - it is shading and protecting your soil, holding water in the soil more than competing with other plants for that water. The deep taproot is breaking through compaction layers, pulling up nutrients. The entire root system is putting exudates into the soil that support the soil biology. In other words, it is a net contributor to the soil food web and overall beneficial for the growth of plants, any plants, in the soil.

I think that low growing plants that cover the ground, but don't shade out our crop plants, are pretty much beneficial. Climbing plants that are going to climb up my crops? Not so much, but even there, we can use corn or sunflowers as support for beans to climb up, so you have to consider your specifics. Fast growing grasses that spread aggressively through rhizomes and grow both dense and tall? If they are out in a pasture, and livestock like them, they are a good thing. If they are coming into my garden beds where I am trying to grow radishes, then they are a problem.

So much depends on context. Whether you use a dead mulch to cover the bare soil or allow a living mulch to develop, I think it very important to have that soil cover. Given a choice of bare ground or weeds, I would lean toward weeds. More life in the soil, cooler soil temperatures, less water loss to evaporation, better water holding capacity in the soil. No benefits to bare earth.

Thank you. I have some kind of grass growing on the edges of my garden bed, but it's hard to tell by just looking if the productive plants are being affected either positively or negatively. I guess it's having no effect one way or another

In my experience grass is worse than normal "weeds" - the dense roots of grass are very greedy for nutrients and moisture and don't leave much space for other desirable plants. Our vegiie beds were fr year made of raised beds with grass paths between. I seemed to spend all my time dealing with the issues caused by the grass paths. They were too narrow to comfortably get the mower down and the grass was always trying to invade the veggie beds. On the other hand we have copious amounts of self seeded forget-me-nots. They keep the soil moist, root lightly and seem to play nicely with other plants.

In our orchard areas I have been making much circle around some fruit trees. There seems to be a big difference in tree vigour and fruit set which I put down to better moisture retention and less root zone competition. We have had comfrey established in the mulch areas for a couple of years now and they seem to help suppress the grass invasions.

Pretty well documented that grass and trees are not very compatable. Savannah may seem like it argues against that, but I would suggest savannah shows what things look like when grass and trees stalemate, with neither able to dominate.

If the grass starts working into the beds from the walkways, I would cut back or pull the grass from the beds. I also tend to mulch my walkways to keep weeds to a minimum in the walkways. I also go with very narrow walkways.