[rco8786]

As others mentioned, normalization is generally about saving space not increasing performance.

That said I’m 100% positive that all those key value pairs are indexed for searching and querying purposes.

[RhodesianHunter]

Not so much indexed, just columnar.

[rodgerd]

It's also about DRY and accurately modelling the data for general operations. Imagine the difference between a data environment where a GDPR deletion request comes in, and everything has a relation back to customer identity, and one where the customer identity is denormalised out to many places or only implicitly present.