It is a question of memory alignment. 4-byte variables work faster than 2-byte ones. This is the reason why you should use int instead of byte or short for counters and the like.
You should use 2-byte variables only when memory is a bigger concern than speed. And this is the reason why char (which is Unicode in .NET) takes two bytes instead of four.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…