In response to warming maggots in your mouth. I can verify 100% that every angler worth his salt has had to do this during the winter at some stage. We the hardy Britts go fishing in some quite unbelievable conditions here. Not meaning our European cousins don't but I have not fished on the continent to know if they follow the practice.
I have personally fished in a blizzard and caught several fish mid storm. I have started fishing on ground so frozen that the basket had to be hammered through the crust, then as the day progressed and things thawed had to pull the basket back out of sludge to be able to go home.
The only thing I would say about them as food is they have a very thick skin and little nutritional content, but that said food is food.