A few friends are seeing that the chat uses your blizzard real name account instead of your battletag as your name in chat, still verifying if this is just an option, but the game won't give any prompts to disable.
UPDATE 3:
UPDATE 2: Disabling REAL ID on your account management does nothing either
update: the toggle does nothing
AAAAND as soon as I posted, a friend found it;
However, why this is set as default, or how it really works is just a mystery as now.
UPDATE 3:
Did some testing and turning off real ID will still show your name oddly enough. Had my brother and another friend whom I had on Real ID before check my text though and with the option enabled, I came up as my btag and no longer my name. Opting out of real ID seems like the safest bet if you wanna avoid any of that.
UPDATE 2: Disabling REAL ID on your account management does nothing either
update: the toggle does nothing
so I tested it
and the name will still pop up
even if you've turned it off
so when I said something my name showed, when my brother typed in something
his name still showed despite having it turned off
AAAAND as soon as I posted, a friend found it;
However, why this is set as default, or how it really works is just a mystery as now.