This allows using the tool without a compatible python version.
You can even use it in a network, where you have no internet access to download and install the necessary pip packages. ;-)
Just copy the SSH-MITM AppImage on the server, make it executable and start it.
$ wget https://github.com/ssh-mitm/ssh-mitm/releases/download/0.5.5/ssh-mitm-x86_64.AppImage
$ chmod +x ssh-mitm-x86_64.AppImage
$ ./ssh-mitm-x86_64.AppImage