The mechanic was designed with true-to-life systems as a guide. You use the tile placement to affect the game in many instances. Enemy tiles (organs and key physical parts of the body), for example can have modifiers packed into them. The liver (in real life: used by the body to filter out the bad stuff) is an enemy tile that can boost the defense of the tiles surrounding it (the game translated version). So you might place it next to a tile that your opponent needs, just to make their progress more challenging. Or you may place it on a tile that another bug currently fighting, making their next attack less likely to hit.
A different kind of example is that you may draw an anti-inflammatory tile (advil or something like that). By initiating this tile, you may drop all players attack (the drug makes them weaker), but raise their defense (as they become more drug resistant). Good for you, if you have extra to spare, but not for the guy who is low on attack.
Now this does not happen for every tile that you place, so choosing the right tile to pull can be just as important as where you move your bug.
On another note, the manipulation is tracked by tokens so no need to keep tabs. As stats fluctuate there are physical reminders for you, should you approach that tile later in the game. Unless you had some strange desire to do so, most tiles will never get more than 1 or 2 modifiers.