It is only a historical question, a remnant of the first days when I came across the UTFT library. The problem with that approach is that it uses write / read sequences to obtain information from the touch chip; and it refers us to barriers such 32-bit architecture, ARM micros, different operation on the MCU pins, and other delicacies.
Right now, I know there are other better libraries, however I have not explored them since I leaned for other types of screens.
With Teensy 4 it will be a good time to give them some opportunity, just for didactic reasons, and see how far this new board can reach at tremendous base speed: 600 MHz !!.