One advantage of a remote desktop protocol over x11 forwarding is being able to keep the application(s) open and in the same state when you disconnect and connect from another machine or access the host machine.

I haven't really used xrdp, but I have used xpra and have been able to attach to running instances of applications that I left open on the host machine remotely (much like I can reattach to a screen or tmux session remotely).

exactly this. i cant get over why people need to reinvent the wheel again and again.

i dont get why there isnt SPICE implementation outside of libvirt. because, thats even better. i mean - usb redirection, sound, (possibly even 3d accel)...

and suggesting doubt-ware like anydesk or even worse - teamviewer... okay, these last ones make sense in some situations.