I had a few use cases with searching and organizing emails I would have used. For example, I wanted a table of all my Lyft rides from a certain year with distances driven, start/end locations, cost, etc. All that info is available in the email you get after riding, so I figured Gemini could read my emails and organize the info.
Turns out it doesn't work at all. It gave me a random selection of rides, was missing info in some of them, and worst didn't realize it was giving me bad info. Pretty disappointing.