I swam in college and it was a privilege to wear fins. I used to see swimmers come to a recreation center decked out in toys (yep that's right paddles, fins, and a snorkel and whatever else they could put in their swim bag). To be honest, I never used the gadgets. Every coach has their take on the equipment they use, but here is my take.
There's a purpose and a use for all these gadgets, but what people tend to forget is that you're not going to be able to compete with the gadgets. You have to learn to be a good swimmer independently before you rely so heavily on these swim aids. I would always ask my coach in high school, "Can we use fins today?" She would always reply, "Are you going to compete with them?" We would literally do 3000 yards or so with no gadgets. When I look back, it all makes more sense now!
There are ways to diversify your workout with different drills, distances, and intervals, etc. My point in this article is you don't need all this extra stuff to help you improve in the pool. It may help you with some of the aspects of your stroke, but don't need to do a whole hour's workout with gear on in order to feel as though you're improving.