This is ancient history and will probably make me sound older than dirt but when Ubuntu first came out, it felt so easy to install and use. I don’t know that any of the innovations were wholly theirs as other distros were trying the same stuff. But it was the first distro I used that really tried to make it all easy and it felt like a complete OS.
Fedora Core was doing the same stuff and now, we have tons of tools but whether you like it today or not, the early Ubuntu releases were like, “Holy shit. I can partition from the Live CD? What is this witchcraft?” Debian obviously was the core project but little niceties were rare on Linux back then. I did want to install multimedia codecs when I was a teen. I did need guidance and documentation.
Not defending Snaps or whatever here but early Ubuntu was user-friendly and made it easy to transition off Windows ME or whatever was dominant and shitty back then.
A separate shoutout to Chrunchbang for customization and minimalism. That was probably the distro that got me hardcore hooked on Linux. I had enough experience at that point to not need hand holding but it was cool out of the box.