If you think about it, even a VERY tight wrist seal will bridge over prominent tendons, just by the physics of how the elasticity works. One of the keys is to minimize the use of the hands. If your hands spend the whole dive relaxed and out in front of you, you don't put tension on the tendons, and you minimize the leak. If you swim with your hands, the seals just can't work properly.
Of course, if you're doing some kind of working dive or hunting lobsters, you don't have a choice.
Of course, if you're doing some kind of working dive or hunting lobsters, you don't have a choice.