Why are breakpoints caught by the runtime?

[Trass3r via Digitalmars-d]

void main()
{
	asm { int 3; }
}

object.Error: Breakpoint
----------------
0x00402013 in _Dmain at bptest.d(6)
0x00402314 in void rt.dmain2._d_run_main(int, char**, extern (C) 
int function(char[][])*).runAll().void __lambda1()
0x004022E7 in void rt.dmain2._d_run_main(int, char**, extern (C) 
int function(char[][])*).runAll()
0x00402200 in _d_run_main


Is there any good reason to catch that?
I really want the debugger to fire up.