If all your bills are denominated in bitcoin, then no problem to keep all your money in bitcoin -otherwise, if you have bills in dollars, you might be forced to reallocate some of those 100% bitcoins into dollars in order to make good on those bills.. and you may end up making such conversion at a time that is not of your choosing. 

If I walk up to any random business and ask them if they will take bitcoins to settle or to render a good or service, there are pretty low odds that such random business is going to agree to transact with me in bitcoin.. because likely their first response would be, "what's that?"  No one wants to appear dumb, of course, so they might fake it and they may have even heard of it, but they are not set up with an ability to receive bitcoin, an they might be reluctant to set up such ability, especially if they are approached from random peep (namely yours truly) off of the street.