I mainly use them for web viewing...but sometimes I print out the odd photo that turns out really well @ work on the colour laser printer to put up on the wall.
If I was having the photo printed properly (ie. at a lab), I would not print it with the frame as , you suggested, a physical frame is likely to go around it anyway - and it might look a bit funny having both
They're great for viewing online though. I know some people cannot stand frames and feel that a good photo will keep the viewers eyes "in the picture".....and although I agree, I often find that they seem to look that much better with a border/frame around them. I guess it's the equivalent to hanging photos on the wall. Just putting it on the wall without a frame "may" look odd...but a nice frame really sets it off.....IMO.