HBD -> Hive and SBD -> Steem comming soon :)
As for vice versa this also can be done but memo will be needed so user can decide if his Hive should be exchanged to HBD or Steem (ouch). This might lead to mistakes so need to figure it out. Maybe mandatory memo will be needed with every transfer (hbd / steem).
Yeah, I don't see any problem In having to use a memo for these sort of expedited transactions.
Thank you and looking forward for the evolution of this swap.app services. :)