You can drag files into many different places and have the drop action do different things. The compose email interface will automatically attach the dragged files as attachments.
Another minor point: if you use VMWare workstation as I do, you can drag files from the host straight into an Emacs buffer. I’m sure this also works for other hypervisors like Virtualbox.
It does not have indentation at all. It should, but for reasons, it does not. Furthermore, for reasons that strain credulity, it will highlight ERROR nodes with a font lock face, causing endless graphical flashing as you leave your tree-sitter tree in a brief error-state as you type.
I recommend you ditch it unless you have a good reason for using it. The third-party yaml-mode.el is excellent.