A common issue with Debian style distros is that you can install packages easily but it often comes with lots of configuration afterwards. It doesn't "just work"
AUR community scripts are like APT but for less popular programs that aren't supported in the main repos and, more importantly, packages that come with more complete installation scripts with necessary configs and supporting tooling.
Like any OSS community it's benefited most from a lively active community.
ArchLinux is easily the best experience you will find for desktop Linux usage. Plus the Wiki is the best around for Linux.
It's the only distro where using GRSecurity is as simple as installing a package. That's just not possible on Debian.
I'd still use Debian for servers as most VPS companies don't support ArchLinux natively, the set-up process for Arch is a bit intense, and if anyone else needs to get access it's better for portability.
I found Arch has quicker updates to the kernal and overall is super quick to adopt the latest tech. What made me completely switch to Arch for every day use, was the day the GTX 1080 came out, I could set it up on Arch with the beta drivers. If I wanted to do the same on Debian, I had to figure out how to update the kernal to a version not typically used, then find or figure out how to install the beta drivers, etc. Etc.
Debian is more stable, so when I need to do something where I don't need the latest drivers, I like to use it.
Typically, my servers, my company laptop(s), etc.