Probably so it loads faster.
Yes, but after a few dozen apps do this, the system is so encumbered with background processes that it becomes intolerably slow. I’ve got a 3Ghz dual-core P4 with 1 Gig of memory and it takes 3-5 minutes to fully boot.
Linux takes about 45 seconds. That’s why I’m on it this morning. I don’t have the patience for Windows today.