it would be awesome if one could allow file uploads for unregistered users who are joining with a link (and password). I reckon it would be best if you could grant file upload permission to individual users but a general setting for the entire chat room would be just as good.
This would make it very easy to communicate with external customers and quickly discuss files (for example when being dealt with or if there are changes and such). Other than creating a share link an actual discussion with video chat etc. would be much more useful.