> I refuse to believe that disk space is less as it can leverage other libraries in the deps list to load at run time and other can use it too.
If I remember correctly, the argument goes someting like this: modern compilers, i.e. something as recent as the Plan 9 toolchain or a GCC version from this millenium, usually compile in only the necessary code with static linking, and not whole libraries. With dynamic linking, you always have to load the whole library into memory, which supposedly pays off only with heavily used libraries such as libc (e.g. think about how many libraries used by Firefox/Chromium are used by other programs).
So the hope is (combined with a general strive for small programs), since text pages are shared between processes and statically linked programs only include the absolute necessary code you end up with a smaller memory footprint.
(I'm not sure whether you save disk space, but I don't think that would be a problem nowadays. Heck, look at go binaries.)
And I guess, the linker could do more whole-program-optimization on a statically linked program, since all the coude is available.
> For static executable the same dependent library will have to linked to all binaries. Maintenance is a pain in the neck.
Generally you would want to have a proper build system. In case of StaLi, they have one global git repository (/.git). An update is simply "git pull && make install".
I don't know if this process is slower or faster than binary updates, but if they strive for small programs/binaries, then I guess it doesn't matter as much.
Source-based distributions, such as Gentoo, have the advantage that you don't have to wait for someone to publish an upgraded binary, you can compile it yourself, instead. This might give you a slight edge for security vulnerabilities.