You'll probably have a problem with stitch quality if you don't use a foot. The sewing machine stitch quality is made to have something hold the fabric down, even momentarily while the thread is pulled up through it. That's why a lot of long arm machines have a hopping foot - it only presses down while the needle is going through the fabric and pulling the thread up, not between stitches.
And as you mentioned - the safety factor. Machine needles are not meant to be used surgically!