There are no such a thing as indoor/outdoor, all bonsai trees are real trees, born outdoors and they are all fine outdoors. If you plant a bonsai tree in your garden, it will grow to be a real size tree.
You are wrong of course. There Bonsai that cannot grow outside due to the species as our climate would not allow them to survive the frosts etc. Just like lots of houseplants and greenhouse plants that would not survive our winters