RDP is pretty awful in comparison. Consider a use case where you need to have multiple X servers on your display from multiple machines. Using RDP you would have multiple desktops on your display.
Well, depends on how much of RDP Wayland would implement. It certainly supports Seamless Windows:
Remote Programs, also known as remote applications integrated locally (RAIL), is a Remote Desktop Protocol (RDP) feature (as specified in the Remote Desktop Protocol: Basic Connectivity and Graphics Remoting Specification [MS-RDPBCGR]) that presents a remote application as a local user application. RAIL extends the core RDP protocol to deliver this seamless windows experience.