>while EventLogging data gets stored in a different, unrelated way
Not really, This has changed quite a bit as of the last two quarters. Eventlogging data as of recent gets preprocessed and refined similar to how webrequest data is preprocessed and refined. You can have a dashboard on top of some eventlogging schemas on superset in the same way you have a dashboard that displays pageview data on superset. 

See dashboards on superset (user required).

And (again, user required) EL data on druid, this very same data we are talking about, page previews:

>I was going to make the point that #2 already has a processing pipeline established whereas #1 doesn't.
This is incorrect, we mark as "preview" data that we want to exclude from processing, see:
Naming is unfortunate but previews are really "preloads" as in requests we make (and cache locally) and maybe shown to users or not. 

But again, tracking of events is better done on an event based system and EL is such a system.