You literally just italicized "need", and I read it the way you intended it.

That's why tech people italicize stuff.

Please reread my comment. Italicising is, as I said, a nice-to-have. I did not need to italicise need; it's an optional extra in my comment, but I can still communicate effectively without it.

Or, as your reply has highlighted, even with the additional emphasis, people will still fail to read it the way it was intended.

Honestly, the unsatisfying answer is simply because they (i.e. those of us who didn't grow up on IRC, like marketing teams) want to, and are used to being able to do it elsewhere. I'm sure the people who include images in email and set their own fonts and stuff are happy with the upgrade; I can especially relate to that since I used to do some marketing and sales work myself.

I also hate the new input field but I understand why they turned it on globally. But a strong enough want is often indistinguishable from a need.

I myself use them sometimes to emphasize certain parts of the message. They can be very helpful. Many people like bolding certain words in an email as well to emphasize them.

They compromised the part that you already said was not important, not the "entire functional user experience", though?