I get like 500 daily messages between multiple email accounts, and this just does not scale. Some messages are needed once year, monthly, some weekly, some are fed into LLM and automation. It is very convenient to have everything organized into folders.
I really have no time, to look for some esoteric details, in some obscure report, on website that stopped working 5 years ago! I just use full text search over my local email archive!
It also keeps paper trail. If GitHub goes down, or I get fired, I still have most comments and decisions.
Without email I would start reinventing alternatives like RSS.