Nosql and Redis

1.NoSQL

a) Refers to some non-relational databases. High read and write performance, storage will expire, and data will be stored in memory

b) Classification

2.Redis

a) High

Why do we use NOSQL?

Knowing some of the advantages provided by NoSQL (scalability, usability, etc.), I still don’t know why a website wants to use a non-relational database.
Can I get some help, is it best to use an