Does a tea cosy in actuality sustain hold your tea hot/warm or is it merely for prettification?
The purpose is so that you don't burn your hand.
The pad ones do keep the steam in (and those silver ones work extremely well). It will obviously bring cold at some point, but cutting down boil loss will keep it hotter for longer.
Remember other not to put the teapot on a metal surface, it will cool 6-8 times faster.
Answers: Yes it does keep the tea hot but also will kind it taste stewed if kept heat for too long. Watch your hands on the teapot toy with as it gets hugely hot with the cosy on.