What are Emacs best uses?

[Jorge]

Hi.  What are the best uses of Emacs?  I currently use it to compose emails,
manage files, to edit LaTeX, and to edit source code and configuration files.
But Emacs seems to be mediocre at viewing PDFs.  Evince has better search.

  What is Emacs really good for?  Is it a good personal information manager?
Can you manage your information (todo, grocery list, etc.) and sync with a
smartphone?  If you can't sync with a smartphone, how do you manage the
grocery list?

  Is it a good calendar?  Can you easily collaborate with colleagues who use
Google Calendar?

  Is it a good email reader?  Does it work with gmail?

  Is Emacs adapting well to the changing computing landscape?

  Thank you for your attention.