The biggest attraction was how it automagically did hardware detection, also deb was a hell of a lot easier than what Red Hat offered, in the day 'dependency hell' was a real problem.
Also, when Ubuntu came out there was choice of desktops.
I still don't understand why they stopped officially supporting the Kubuntu version, it was and is the most flexible DE.
The recent inclusion of Snap is another dubious move, sure you can work around it but just the idea is flawed.
There are alternatives like Mint and especially Neon but why not keep the conventional Kubuntu as official distro?