This is almost the only advantage. A related "advantage" is forced upgrades when dependencies change - since you can't have code depending on different versions

This is almost the only advantage. A related "advantage" is forced upgrades when dependencies change - since you can't have code depending on different versions of in-repo libraries and services, client code needs to adapt or die. The more clients a library or service has, the more expensive this is, and it's an ongoing maintenance cost for every client. Since people changing the service don't feel the full pain of this maintenance cost, changes keep on happening, and eventually clients get culled because it's too expensive to keep on maintaining them all. From the outside, this looks like the company abandoning venerable but still working product, and makes people scratch their heads, wondering why.