Steem really needs communities if we want large groups of like-minded people to use it. They want to gather around an interest and not necessarily a single account.
They would use far less RC than normal comments, so it makes them useful for smaller accounts, but they could also be leveraged by UIs to allow for 'guest' comments. The UI would still need to reasonably limit spam, but there would be less at stake in terms of resource abuse....( i liked your pust)