Bookmarks might be great for saving links. But what is you wanted to save more than just a link? Like your company's analytics dashboard. Or your personal twitter account.
That's where Saved Cards come into play:
Save Card
Click the name of a card at the top and choose Save Card
Alternatively, you can save a card with the keyboard shortcut "⌘+s" ("ctrl+s" on Windows)
You can name and customize your sessions while saving them
Saved cards will appear in the new card panel and are also accessible through Switch (⌘+L on Mac. ctrl+s on Windows)