I've got mixed feelings about this one, and I can certainly see its benefit, but it goes up against something I need: choice and control. Right now I have full control over quotes being formatted or not. I want to be able to do it how I want, rather than the site "helpfully" deciding for me how things are going to be formatted.
The discussion above about making this configurable means I need to bring this up: I need to know that the formatting I see is the formatting my partner will see. Italics and bold are important communication tools that let us control emphasis; switching them out willy-nilly can change meaning in ways I don't want. This means if a post is saved with "quotes are italicised", everyone should see it with "quotes are italicised". It can't be a viewer-side setting (like whether messages show up in block layout vs inline layout).
I'll provide a case for this, the following message, which has some italics at the end:
Lara opened the case left on their doorstep. "It's... a ram's head?" After a deathly silence she whirled, pale-faced, and grabbed her colleague. *"Shit, Tom! We need to get the hell out of here!!"*
The intended reading is this:
Lara opened the case left on their doorstep. "It's... a ram's head?" After a deathly silence she whirled, pale-faced, and grabbed her colleague. "Shit, Tom! We need to get the hell out of here!!"
The italics help reinforce the urgency in her voice. If it's a viewer-side setting, someone with "quotes are italicised" gets this output because the quotes inverted themselves:
Lara opened the case left on their doorstep. "It's... a ram's head?" After a deathly silence she whirled, pale-faced, and grabbed her colleague. "Shit, Tom! We need to get the hell out of here!!"
The emphasis got put in different places and some of my intended meaning is lost. This is part of that "I want to have control" thing I was talking about above.
And if you had viewer-side configuration over whether quotes are italicised or not right now, those of you with it enabled might be a bit confused and would probably have to turn it off to read this post the way it was intended to be read. In other circumstances, you wouldn't be sure whether "on" or "off" would give you the intended meaning.