At some point in time I guess it will become either one thing or the other. It cannot stay both at the same time. Can it? Is it a healthy usage method to have it as both?
I don't think it's possible that bitcoin will be used for both investments and payments since these two things don't work well together. Think about a store who at the end of the day have collected 1 bitcoin for example. Next day in the morning when they want to exchange that bitcoin into dollars to buy more merchandise or even if they use bitcoin for that the value of that bitcoin could have dropped over the night with 10% so their income also dropped with 10%.