The primary use for our chartplotter is as a bookend on our shelves. It does it's job well.
Most of our sailing is daylight and we are primarily paper chart users. We rarely have it on due to the power draw. If we had solar or wind generation on the boat that might change our usage but I doubt it. With the LED and cold cathode ray fluorescent lighting on board we are able to go almost a week without charging the batteries. The CP would cut into that. Would rather save the juice for the autopilot.
We do use our chartplotter in stormy weather or when sailing at night as an aid. When the chartplotter is on the radar unit is also generally up as well. We like to confirm our track on the paper chart using the GPS in those conditions. But it is never our primary navigation device. It only takes one error. If I do not know where I am then I stop the boat or reverse course before relying on the GPS to close on an obstruction.
We view it as one of the many options marketed to sailors for our pleasure and enjoyment. Many times we think the items are vital. Look at the magazines - everything is.
My wife and I asked ourselves last season if the next boat we buy does not have one would we purchase one? The debate is not over but I would guess probably. Because when I used the term aid I meant that under those conditions it can be a real help and provide peace of mind.
It's better to have your enemies inside your tent pissing out than outside your tent pissing in...