Well, I’d find it handy. What I’d like my email client to do would be to automatically, when requested, recognise dates and times and add them to whatever calendar system I’m using. I’m always receiving emails with this sort of information. I know that there is a plugin thing for Outlook, but I use Thunderbird, and so far I have not found a system that can do this.
Such a system would save quite a bit of time for many people, I suspect.