1) It provides a plethora of information to potential hackers as they can see literally every incoming request and can find admin pages and such.

2) Exposes every visitor's IP and the URL they're visiting to everyone. If more sites did this people's browsing history day-to-day would be exposed.

Also as someone mentioned above, this is clearly a bad configuration issue -- this page is supposed to be password protected or IP restricted (to localhost by default in Apache). At the very least, the visitor IPs need to be masked.