RE: peep site
For me, a peep site is a great help. It basically forces you to get the same anchor point each time. Without a peep you are more prone to not hold the bow exactly the same each time, even with an anchor point. You can hold the bow at different angles, etc.
The peep basically acts like the rear site on a gun. Technically you could shoot a gun without a rear site if you held the gun the EXACT same way each time, but why bother when the rear site makes it easier and quicker?
Others are correct, though. You don't have to have one, it just makes lining up a shot quicker and more accurate for many of us. Others see the peep as a hinderance, but it takes quite a bit of discipline to get that anchor perfect without a peep.