There is no lack of package management. There is a lack of automatic dependency resolution without third-party additions. This is nowhere near as debilitating as often presented by outside observers who have never tried the distribution.
YMMV, but I've ran into circular dependencies and conflicts in addition to configuration updates rendering systems unbootable multiple times on distros like Debian with their non-transactional resolution heuristics that make your life easier, until they don't. Slackware's spartan package management has not failed me once, it's rock solid no matter how much you thrash your file system hierarchy. In addition, when I want to install SlackBuilds, I have never used a more convenient package manager than sbopkg before. Dependencies can be cleanly recorded and built with queuefiles.
Slackbuilds.org will tell you if one of the packages there has dependencies that aren't in Slackware. Typically installing them is not onerous.
As for other uses... using it to reply to this comment right now.