In my house there are many rooms. If it is not so, I would not tell you so. In all the rooms there are many cupboards. Most of them are made of wood. Some of the cupboards shelves are not of good quality wood and would bend due the heavy weight put on it. I wanted to buy a metal shelves but has yet to do so until now. It is alright to put metal shelves inside the room.
Would I put metal cabinets in the kitchen? The answer depends on one factor. Whether the kitchen is meant to be used as dry or wet kitchen. If it is used as wet kitchen then I would not put metal cabinets in it. I will rust easily once it got wet. It is okay to put metal cabinets in dry kitchen. In fact it would make the kitchen more presentable especially if you have the stainless steel cabinets.