Quoted from wiredoug:why would i use one at all? ( got me wondering now what im missing haha)... hand drill and a good aim seems to do all i need on a machine.
When precision matters. Much easier to be precise in every dimension - positioning, being square, depth... Also, you can clamp down your work piece which for those hard to drill pieces keeps everything way more stable. It also lets you focus on just one of the above dimensions at a time.