To expand on that, it produces dynamically linked binaries so you do need libevent, libpcre, libgc etc. when you want to run crystal binaries. We hope to get the number of runtime dependencies down in the future.
--link-flags="static"
The output binary is bigger than dynamic linked and it would needs some dev libraries before compile.
Requiring the user to install a separate bunch of dependencies adds a huge amount of distribution friction vis-a-vis just shipping a stand-alone application bundle, especially in this day of app stores. Being able to avoid that is very important, IMO.
Probably anyone reading this isn't going to be daunted by having to install some extra stuff, but for the average user it's a real pain.