It's convenient to use this one clock frequency, no doubt about it. However, it's possible to provide a standard baud rate without it, if it's really important to do so.
It is NOT if you do not have a free T2

However, so many app's use this frequency, and I see plenty of them in ad's and technical papers that cross my desk all the time, that don't even use the serial port, though they all seem to provide one. It simply troubles me that so many people are willing to slave their system timebase to a frequency that is non-essential to their application.
if you use (as you yourself state to prefer) a "universal" board, the part of universality id the ability to communicate serially

Marketing literature frequently trumpets the "high-performance" of their MCU, yet when the evaluation board is published, it has that 11.05 MHz (or a harmonic of it) crystal. The MCU can operate at 24 MHz, but it comes with a 22.1 MHz crystal. It's not even a 10% difference, but you'd think they'd want to demonstrate their product at the extreme.
I doubt they would want to demonstarte that their product could not communicate serially eventhough it has a UART. 10% off makes serial comm impossible

I've seen 805x-core MCU's that operate "under the hood" in automobiles that don't even need to adhere to that frequency "standard" yet they have that crystal on board.
What i manufacture for "under the hood" communicate with the rest via 9600 J1708

Erik