I seldom supplement food with fish. If I know there is a possiblity of it and I am fishing I will take the stuff, but I will take light meals and then add trout to it. I won't rely on
caught fish as a meal substitute.

It does however, depend a lot on where you are going and what you are doing. If you are hiking mostly, and fishing occasionally, you may find you don't want to expend the effort. or rely on catching fish you may not want to expend time to catch.

If you are doing somewhere to known backcountry fishing locations to spend most of your time fishing, then of course! if you get low on food it's because the fishing was bad and you probably want to walk out anyway..