Having a single spot where broadly useful data can live is sort of the point of OSM.
Grab would already be using the OSM data in bulk to host their own services. That's sort of the model that the OSM community has pursued, the openstreetmap.org website and associated services are a tech demo with no service guarantee, so you wouldn't want to rely on them much for a business.
But then the data is tied up in their proprietary service. Like, I appreciate the attempt to contribute this kind of thing back, even if it was a bit ham-fisted.
Grab would already be using the OSM data in bulk to host their own services. That's sort of the model that the OSM community has pursued, the openstreetmap.org website and associated services are a tech demo with no service guarantee, so you wouldn't want to rely on them much for a business.