Why doesn't substitute-path config option apply to breakpoints?

[bitwombat]

I work in /source which is symlinked to /mnt/source. As we can see from many old issues, this causes breakpoints to be ignored.

I was hoping the substitute-path option in the config.yml would fix it, but text right above says:

Note that substitution rules will not be used for paths passed to "break" and "trace" commands.

Why is that, and is it going to be changed/fixed someday?