Is there any reason to not limit a games framerate to your monitors refresh rate?

There are a couple of advantages:

• Reduced input lag (the time between pressing a button, and seeing the game react to it).
  This requires V-sync to be turned off, which may cause heavy tearing.
  

• You always see the newest state of the game.
  This requires either V-sync to be turned off, or Triple Buffering to be enabled.

As you can probably tell from the accepted answer in the question you linked to, unlocking the framerate comes at the cost of higher power consumption, higher heat generation, and may result in higher noise production.

Whether the advantages are worth it, is different from person to person.