Hell yeah bro! Machine embroidery thread is great for decorative stitching! It behaves a little differently than sewing thread, and rayon embroidery thread is substantialially weaker in tensile strength and more likely to fray compared to polyester embroidery thread. Make sure you use an embroidery needle, although metallic needles work well too, sometimes better. Another helpful tip for fuss-free sewing with embroidery thread is to use a silicone oil thread lubricant, like Sewer’s Aid, to reduce forces on the thread that may cause it to break or stitch poorly.
Remember, machine embroidery thread has less tensile strength than an equivalent weight sewing thread, so keep that in mind if you’re using it in a pinch to fix a ripped seam an hour before a fancy party.
Oh and I use the hell out of, I guess what you call hand embroidery thread. Madeira/Tacony marketed this super thick stuff on spools. You could wind it onto bobbins and load it into specially-modified bobbin cases, and do some cool decorative stitching effects evocative of TIG welding. It would also work in the self-threading Baby Lock overlocks and Sashiko machine and it looked awesome.