It is "line training" and it is "hour building". It is merely an extension of your training but most importantly:-
It is "EXPERIENCE"
Putting your hand in your pocket for a CPL etc is absolutely no different to putting your hand in your pocket for Line Experience.
Everyone's perspective is different whether you are a 23 year old Oxford Graduate with your balls on fire or you are a 45 year old accountant who has always dreamed of being a pilot.
That's me off my soapbox.