Wondering why Portals aren't shown on map(s)?

[Kreelor]

Hi. I'm wondering why most Portals are not shown on Carbonite's map(s)? Blizzard's map doesn't show Portals either.

Since Portals are so valuable to traveling long distances, I would think they would always be shown. Not everyone plays a Mage. heh heh

I'm using Carbonite version 5102.