Agreed that Communities and SMTs are technically not interlinked, but I do think that Communities provide a comprehensible proof of concept for SMTs. Almost any effective token system will be part of a "community" of some kind. So while, Communities and SMTs are technically distinct, I do believe that Communities will have a very compelling implementation of SMTs that will be broadly comprehensible to a wide variety of people. Thanks for this very thoughtful comment.
AFAIK light accounts would be wallet addresses that can send and receive tokens and nothing more. This is the only implementation I've heard actively discussed with our blockchain devs and they were not at all under the impression that it is nonsensical. An implementation of light accounts is definitely possible, not difficult even, and in high demand by every 3rd party app developer we have discussed this idea with.
Light accounts are not something we believe we need for steemit.com, but Steem is about far more than steemit.com now and we want to make sure that the Steem blockchain is the best protocol for developers. So we are eager to integrate any feedback from them that we can, as long as it has the support of the larger community and Witnesses.
Start with communities first, that's easier to understand for the end user.
"Communities are like a subreddit, but with the difference that the moderator(s) can monetize their efforts curating quality content".
Then bring SMTs, once communities are big enough they could find usage in a token rewarding their users in whatever way they find contributing.