A common use of toaster ovens is to warm plates, actually. A big advantage of toaster ovens is that they heat up much more quickly than conventional ovens, which has the additional effect of using far less energy. Good toaster ovens can do nearly anything a typical convection oven can do, just with limited capacity, making them much more efficient (both time and energy). And a good toaster oven can definitely outperform a bad traditional oven.

I'd imagine toasters are probably just as big fire hazards, so IMO it's about buying quality and being prepared in the event of emergency - which should really be the case for anything in the kitchen.