An advantage of dynamic libraries is that the memory used to hold the library's executable pages can be shared across processes. So using static only binaries will lead to less free memory on the OS.
Linking to a shared library brings in and initializes the whole library, even if you only need one function from it. So you tend to get stuff paged in during load that never gets used.
Isn't it? Usually distros target their packages to a single library version, and often people run suites (Gnome, KDE, etc) that use a similar set of libraries in their different processes.
Desktop would be crippled if every app was compiled with the whole stack of X, toolkit and Gnome libraries linked in statically.