The name and abstract is slightly inaccurate/misleading. This module is supposed to be a general logging framework instead of just subroutine entry/exit tracer. For alternative subroutine tracer, I'd recommend Devel::TraceSubs or Devel::TraceCalls (or even Devel::Trace + variants).
Not very convenient to use. It still requires you to put 'if $App::Trace' clause everytime. For general logging that can be switched on/off upon runtime, I'd recommend using Log::Any instead.
Lastly, this module is tied to App::Options and thus only really usable if you use both.
If you want to trace the calls of your subroutines it's IMHO better to use something like Devel::TraceSubs as it allows you to add/remove the loggin without haveing to make any changes to the traced subroutines.