There are times it's really useful to access email from a terminal, and terminals are widely available (shell on your primary system, Termux on Android, SSH to your email host, whatevs).

It's also often convenient to either script interactions, or to have full access to shell tools when interacting with email. I practice this more often with mutt, but I can filter either messages or metadata (headers) and send those to an awk or sed pipeline to extract specific information of interest (this is especially useful with notifications / alert emails). This might be tens, hundreds, thousands, or more messages that are of interest.

Full-blown GUI or Web client email tools are pretty, but lack this flexibility.