It's slow, but not that slow if you compare it to trying to do finiky corners and details on the machine, which always come out wodgy with creases to make everything line up. And there is much less overhead than setting up the sewing machine.
Many years ago, at least 10 probably, we were visiting Jesse's friends for new years, and Beth was hand sewing a duvet cover. I thought she was absolutely crazy, to do all that straight stitching by hand when you could go through the entire thing in 10 minutes on the machine, but now I think I could get into it.