Why the core must be paused in order to edit any PS2 memory with the Debugger of PCSX2?

[ghost]

In PCSX2 1.6.0 I remember that I always had to click on the "Break" button before I could edit the memory of any PS2 rom that I wanted to hack.

Even the "Assemble Opcode" context menu is unavailable while the core is running.

Why PCSX2 forbids me to edit PS2 memory while the core is running?

wheremyfoodat said here:

A lot of people, including me, very often edit memory that's safe to edit while the emulator is running.