Yes, we're excited about the possibilities of an end-to-end use case as well... in fact we were surprised when we found a lot of interest in front-end output layers on top of the APIs than just the APIs themselves. Would be curious to know what output features would be most valuable for you.
Well. Think about spreadsheets. Think about live spreadsheets powered directly by APIs. Bingo!
I'm doing a couple of data mining projects right now and simply being able to query and look into the API outputs, as well as my local database, without building a custom frontend would've saved me a bunch of time. But I'm thinking more of the knowledge worker, or even the power user who wants to view their Fitbit, Up and Lark data all in the same dashboard. Can't help but thinking this already exists somewhere though.