Technology (FHE)

While reading the documents, I found the technology being implemented in zam interesting, but I have some questions!!

What exactly does “fully homomorphic encryption” mean in simple terms? How is it different from regular encryption?

Why is fully homomorphic encryption (fhe) called the “holy grail” of cryptography?

Is fhe really secure against hackers or quantum computers?

If so, how does it do that, if we don’t have quantum personal computers yet?!

What are the main limitations of fhe? Why is it slower than other methods?

How does zama ensure that fhe is easy to use for people who don’t understand cryptography?