Comment by wolrah
DisplayPort has supported HDCP (as well as its own DRM scheme DPCP) since version 1.1.
I agree that DisplayPort was better for monitors, but HDMI has basically become DisplayPort so these days they're more or less two sides of the same coin. Both use data packets over fixed rate links now.
You may be thinking of HDMI vs DisplayPort over USB-C, because otherwise they couldn't be more different. In any case, HDMI is still heavily patent and royalty encumbered, to the point it is going to be difficult for opensource GPU drivers to support native HDMI 2.1 or higher going on, while DisplayPort is still royalty free.
The situation is so bad Intel has pretty much skipped native HDMI ports in recent chipset graphics to focus on DP only (motherboards can still install off the shelf DP->HDMI converters), while on AMD the newer HDMI features won't be supported at all on Linux.