One of the most immediate benefits of wearing fins while swimming is an almost effortless and substantial gain in speed.
When
learning to swim, it can be challenging to keep going, especially when your kick isn't that strong or effective yet.
Thanks to the added surface area from swimming fins, your legs can create a more powerful kick. The wider surface area means that with every kick, you can move more water, and as such, you may go faster than you would with your bare feet.
For a beginner, this increase in speed makes an unbelievable difference. You will feel like you can swim at a pace that makes staying on top of the water much more manageable.
The added speed would help you focus on other more critical parts of your technique, like that arm stroke or your breathing, without getting frustrated with slow progress.
Eventually, as you develop more confidence, the kick becomes much more effective, even without the fins.