[lubujackson]

Some good answers here, but I hate that this has been downvoted. It is a valid and reasonable question - we shouldn't be downvoting questions like some echo chamber Reddit thread.

Prime numbers are a core and mysterious numeric progression that has the unique property of being very taxing to determine the factors of any sufficiently large number. This is why they are used in cryptography. Investigations into the nature of primes has produced many mathematical tools and they have bridged many different areas of mathematics together.

But the simplest answer is that prime numbers are a tantalizing mystery that is easy for anyone to understand. The deeper you dig, the deeper the hole gets and it almost doesn't matter if a satisfying "answer" is ever found. Primes are a McGuffin that has led to countless discoveries.