Yep, I believe the passport "card" is meant to be something of a quick border check for land crossings to Mexico and Canada. Those two coutries used to only require ID (like a driver's license) but they upped the requirement to passport - but they added the "passport card" as a compromise for the people who cross often but can't afford a real passport.
The folio passport (regular passport) will get you anywhere you are allowed to go - it is always the best option.
I am the editor, but I also speculate, ask questions and play devil's advocate. I reserve the right to change my mind.