Encrypted Data - Is That a Common Practice?

There are clean room environments that could also operate on encrypted data and there's different variants of these. Having a third party is a nice part of this because, you know, even though I have to trust the third party, there's not a lot of motivation to be the man in the middle. Do people tend to take other steps as well? Like maybe we should hash the emails before we send those and then you compute on this hashed value.