It is obvious that power reserve indicators on watches were inspired by the ones used on ships chronometers.
These are manually wound high precision clocks that usually have a two day movement and although of fusee type, need to be wound every day.
This is usually the task of the 2nd or 3rd mate and as a ships captain, because of the indicator, I would be able to check if this had been done, without messing about with the movement more than necessary. (To wind them, you have to turn them upside down)
Now, with this in mind I have always wondered why these indicators suddenly appeared on automatic watches like IWC's and others. It seems to me that they are there for the sole purpose of beiing there.
I mean, if you wear it every day, the indicator is useless and if you don't, the watch will eventually run down and stop anyway!? The whole purpose of an automatic watch is to take your mind off the fact wheather the watch is wound or not. In that case the indicator just makes it possible to check something that shouldn't need checking.
Just a thought.