I can appreciate LLMs for some use cases, but writing emails for the user is the one that really baffles me. It's one thing if you don't speak English well and could use some help making yourself understood, but the amount of native speakers using this is so strange to me. How does this help you? If you can write to the LLM telling it what kind of email to write, you might as well just write the email.
I don't use gmail but often get an LLM to write certain emails. The benefit is that it can pull in context and typically one-shot the email without me prompting it at all.
For example, a tenant emails me about some issue relating to a specific property. It can go through my leases, find the right one, check other emails to see I ordered a new appliance to that specific address, track shipping/install, all that, then reply appropriately.