That, among other things.
HUD Minimaps floating at the end of your screen just takes away attention from the environment, and graciously delivers it to that ugly pacman-ish minimap. Do we need the player mainly focusing on primitive and simple graphics that serve no purpose other than to make the game easier, or do we want the player completely focused and immersed in the environment our game proudly creates?
If I wanted to play a minimap game, I would be playing games from 30 years ago. And those games are still more immersive in their own specific world, exactly because they offer a direct way of playing the game. The "meta" game of minimaps diverts attention away from the game.
My previous post here gives attention to the fact that games are usually filled with other games, minigames that branch out of each other and influence one another, but a successful game is a game that guides the players attention, through the minigames, towards the main presence in the game. Minimaps do the exact opposite. Immersion means bringing the necessity of attention to the actual game and the immediate presence in the games environments. Getting lost and learning how to navigate throughout the world is one of the most rewarding experiences in games of the recent past. It also is a very good trait to learn, today I rarely get lost in very new and confusing environments because of games that needed direct attention.