On the point of simplicity, much pain has been described here about running Jenkins - https://www.cloudbees.com/products/cloudbees-jenkins-distrib... is hopefully a better way to handle that.

On kubernetes - imagine if that was already managed for you, all the powerful things that can be done on top vs your self (preview apps, owasp vulnerability testing, progressive delivery - all without writing a pipeline - this is stuff that can be done.

I note gitlab is mentioned a lot here: they noted this power as well (see auto devops) and have started building things on top of kubernetes too.