Yes. I saw that TED talk about desertification being reversed by ruminants, and while it got a lot of critics, it had some pretty good points. But, those ruminants would be better off not being beef cattle in terms of biodiversity. Also, if they were beef cattle due to the lack of anything better, hopefully it would be short term, and if you're making a case for use of marginal land, they really shouldn't be finished in a feed lot, since that is using a lot of cropland to support that.

... and only some places would (possibly) benefit from that.

I think cattle are fine... though I'm also okay with more Bison, goats, sheep, deer, elk, etc. I'm also more than okay with less use of feed lots and direct butchery of grass fed ruminants.

As for marginal land... personally, I can only handle mostly eating meat and eggs, doing much better with ruminants. I'd be just fine with the majority of uninhabited lands being used by mostly wild ruminants over any kind of farming, especially farming that is using chemical fertilizers and stripping the land.