"It depends" some rock is net beneficial, can be both structural, physical-chemical effects on soil regarding clumping and water retention, and bio active (supporting beneficial micro-organisms, providing micro nutrients)
Some phosphate rich rocks might be also known as.. fertiliser.
Arsenous rocks would be a disaster. It's a huge issue in India with water table and ground contamination. Likewise lead, or salt (in the wider sense if it causes brackish ground water) although that's about deep wells. I have no idea if this is a serious risk for rockdust plans.
For enough upside benefit downsides might have to be borne or mitigated.
The type of rock dust they are talking about is already commonly used as a soil amendment to add trace elements and minerals. That said it is possible I suppose that the optimal amount for carbon drawdown is greater than the optimal amount for crop health or yields
Basalt is mentioned in the article. I know just a little bit about farming and growing things but I don't know anything about this rock stuff. But if it's good (or, perhaps, at least not bad) for the crops then it does seem like a possible good idea.
Some phosphate rich rocks might be also known as.. fertiliser.
Arsenous rocks would be a disaster. It's a huge issue in India with water table and ground contamination. Likewise lead, or salt (in the wider sense if it causes brackish ground water) although that's about deep wells. I have no idea if this is a serious risk for rockdust plans.
For enough upside benefit downsides might have to be borne or mitigated.