Good question... I check the "Enable the remote control of applications" option for each employee as it allows me to perform Admin tasks via RC meetings desktop sharing when a UNC prompt comes up. Without it checked, as admin you cannot type your account information when prompted... keyboard is disabled. Not sure about the "Remote Support" option... it may allow the "Remote Support" button to display at the top of the sharing screen when in a meeting for users.
So Remote Support allows you to do way more than the "Enable the remote control of applications". I'll go through some of the things I saw when testing it out briefly and you can check out the article I linked you as well :)
So when you enable Remote Support, you will see this option in your RingCentral Meeting:
Once my colleague (who has Admin rights on his own PC) approved my request for control, he was prompted to enter his Admin Credentials. So, I'm not sure how that step looks if the Attendee does not have Admin Rights on their PC. Once I took over I had free reign and then when I clicked on the Support button again, I saw these options:
From our brief testing, Remote Support is very useful for doing things that an IT department would do when troubleshooting someone's PC. The "Enable the remote control of applications" option didn't have any of the options above so I believe it is limited in its capability. Hope that helps!