I overwinterd koi and goldfish "and cool water cichlids" in kiddy pools in my basement, because in Milwaukee my ponds froze solid 3 ft below the ground level.
In theory, goldfish are healthier at cooler temps originating in China, but so do paradise gouramis, many barbs, weather loaches, high fin sharks etc etc.
And the cichlids of southern South America also come from cooler waters.
Many of the "braziliensus complex, Gymnogeophagus, Australoheros and some Pike cichlids, even the piranha like tetras of Uruguay, are cool water species. So depending on how geographically correct, you want your tank to be.

I personally don't mix fish from different continents in a display tank, it always looks a bit off, but in non-display I can be just as hypocritical as the next guy.