Very significant impact. There is no silver bullet that can remove the excess emissions on it's own, however combinations of these removal methods (coupled with decarbonization of course) will be essential to addressing excess atmospheric CO₂.

Regarding economics; there is plenty of olivine rock already available as a mining by-product. Disadvantages are that it takes up to 1000 years to fully sequester however this is logarithmic with a large portion of this achievable in the first century (why they mention 75 years in this article). This can be accelerated with further grinding to increase surface area.

I would imagine that regulations for net-zero will push for carbon removals to be sold similar to carbon credits have been (as net-zero can only be achieved with removals, not credits). These could either be sold as they are created annually or pre-purchased as the mineralization is a pretty sure thing to happen.

Whether this (as in CO₂ removal, not limited to enhanced rock weathering) evolves into a public service equivalent to garbage collection or a utility like water is yet to be seen.