I’ll give you one reason for using Gentoo: option of no systemd.
Gentoo is one of the few distros which still offer a systemdless setup given its nature of high configurability. You can tell the system-wide config file to exclude systemd support in every package it attemps to compile.
I hope you or anyone who just enjoys their linux machine running fine and happily, now be able to see what freedom can mean in the open source universe. Cheers.