Wrist strap releases do help you pull the string of the bow with less fatigue on your hand. Because the weight is displaced around your wrist you will not feel the pressure on your fingers as you would with a tab or finger grip release. This translates into being able to hold your bow at draw for as long as your back and arm strength will allow. Can you pull more weight with a release? I don' t know, can you? If you go to a shop that will fit you and your bow with the correct equipment (string loop, maybe shorten the draw, adjust the release, etc) you can have them up the poundage of your bow until you feel comfortable. (for this reason alone I would buy the release from a good archery shop with a shooting range.)

There are almost no disadvantages to getting a release that I have found. Try out a few to find one that fits your style and hand. good luck!