Biggest advantages I know of for dynamic linking:

* You can use the LD_PRELOAD trick to override behavior at runtime.

* You can run with entirely different implementations of the dynamically linked library in different places.

* Software can pick up interface-compatible upgrades to its dependencies without being re-compiled and distributed again.

We use all three of these tricks in our SDKs, FWIW. But it is still a giant pain in the ass.