Well to be honest, 100% swings in a day are TERRIBLE for a means of exchange. Price stability is very important for exchange. If you can't even worry about buying or selling because you are worried that your bitcoins will change in value in a day or week it is bad news. I dont think bitcoins primary function is a store of value, so that doesn't bother me. I would much rather have them stable and at $5 then swinging between $50 and $100 all the time.