Because the person I wrote this little thing for wanted it to be seperate so he can modify his getinfo() method without touching the add(). He doesnt always parse the same paremeter to the add() method. He added to his code so there are differences. For example, I have just $this->getinfo(); in here but he had a few extra methods inside the getinfo method to seperate pages and the counting.

Yes, this will generate a big file if you just keep it running, a better thing to do would be to only save the count for Unique hits in which it will avoid all the page views.

There are better hitcounters and such on the internet, I've messed with google analytics, it is pretty good I should say but not the best. Its got some downfalls, I currently use Mint from http://www.haveamint.com/, check them out they have an amazing tool for web tracking.