Why same pointer type for GC and manual memory?

[IGotD-]

I'm trying to find the rationale why GC pointers (should be names 
managed pointers) are using the exact same type as any other 
pointer.

Doesn't this limit the ability to change the default GC type?
Doesn't this confusion make GC pointers just as unsafe as raw 
pointers?
Has there been any prior discussion about introducing managed 
pointers in D?