Mike, Dave and I (honest, I ain't referring to myself twice) both have the same model drillpress. Maybe others are better.
I found mounting and demounting the attachment to be a significant pain in the neck (among other things, the chuck had to be removed and reinstalled each time). Aligning the fence of the attachment was another pain.
Look at the length of the handle on a mortiser, then on a drill press, there's a huge difference. Drill press doesn't need that much leverage, it doesn't normally ram a chisel through wood.
Everyone's mileage varies though. What I find to be an intolerable pain, others may find a minor annoyance. Kind of like the "worth" part of your question, because I know there are many who think I'm insane for my mortise and tenon solution, a Leigh FMT for $800...
Dave