Comment by petcat

Protons email encryption is mostly snakeoil and marketing. Their guarantees of strict encryption at rest is really only relevant to a certain class of people with a very specific threat model. Everyone else that uses the service is just leaking plain text email with everyone they converse with who uses a service that does not offer the same encryption guarantees.

So basically they sacrifice a usable search function for a security service that isn't relevant to 99% of people and isn't even effective half the time.