Rex..you should really put your inner nerd on time-out.
For the why does it matter argument, Infantry does not just assault. We are also key info finders. In order for infantry to do this well, he has to be able to blend in, the base uniform matters. Ghillie suits are great for there intended role, but there intended role does not cover all situations were infantry need to blend in. Ghillie suits snag and can leave a traceble trail when worn on movement. They also reduce movement.