> Grass fed cattle can use land that is generally not fit for vegetation farming

Can, but that doesn't mean it always is. There's lots of cattle that never even comes outside, and is fed food that humans could also eat.

I recall reading that during the famine in Ethiopia in the 1980s, Ethiopian farmers were exporting beans to feed cattle in Europe because that was more profitable than feeding people in Ethiopia.

Beef is simply extremely inefficient. And so, unfortunately, is cheese (I can do without beef, but not without cheese). If cattle is grazing on land that's simply not usable for anything else, that's a completely different matter, but that's not how most cattle are fed.