Yes hot glue does conduct electricity but not very well. If you are working with delicate electronics were the electrical current must be precise then it can cause a problem. However if you are just working with a battery a switch and a light bulb it is usually fine thought I have know it to cause the occasional short in even the simplest of wiring.
I have had to use several electrical props,and hot-glue together in my career as a pro prop-maker,and yes,it will conduct voltage.What we do,is coat the elec. prop with latex,to insulate,but,saran wrap will do the job.