What is the purpose of qvm-console in Qubes 4.3? All I have is this:
Usage: /usr/bin/qvm-console vmname
Connects to another VM console using the admin.vm.Console RPC service.
And all I get is that it Cannot connect to <QUBE_NAME>
I got used to type qvm-con<TAB> to get qvm-console-dispvm 
qvm-console you can do from within a terminal, which means that your terminal will be directly connected to the console of another qube. Not recommended for security as it allows the destination qube to send escape characters to the caller. What is missing (on purpose) is to allow admin.vm.Console policy with redirection of the target to dom0.
In other words, qvm-console-dispvm connect the console to a disposable instead of connecting directly to the caller, guaranteeing isolation.