- no presence or typing indicators
- no working end to end encryption, definitely so for group threads
- no reasonable concept of managing groups
- no standard way of quoting
- inefficient or unsafe media sharing
- insane amounts of spam
- no lightweight formatting
- no avatars
And that's just what randomly came to mind.
E-mail sucks for almost anything.
Ever tried sending a message that's several pages long on anything but email? Go ahead, do it. See how <your preferred messenger> hits the ground face down on that.
Even your short comment is too long to be comfortably read in most IM apps.
>- no standard way of quoting
Using > is a de-facto standard. Now, I know, you have objections. Before you voice them, try receiving a long message in your IM of choice, and try writing a response quoting parts of the long message you just got. Could you manage to do it in a single message? Ah.
Some of use like to write, you know. And email is good for that.
Almost anything else sucks.
> Some of use like to write, you know.
/r/iamverysmart . Some of us like to write short messages quickly, you know. With read receipts and push notifications.