I took a look at it when starting work on those features, but decided against it. I wanted as much freedom as possible in storing, accessing, and displaying data since we'll need to build something more sophisticated in terms of analytics later on.

We use our analytics engine to show charts to our users as well. I can't do that with graphs generated from tools like Cacti/Ganglia/Graphite... As is the case with almost all sysadmin tools, they don't look too good.