It is profitable, but not when you get greedy.
If you send 1 SBD - then you will receive x2 at 0% Curation. Which results in 2$ value and 1 SBD Payout.
If you send 1 SBD - and your post is already older then you will receive x2.6 at 25% curation. Which results in 2.6$ value and 0.95 SBD payout. Which is still a lot - if you think about how much you will get additionally through Steempower.
So please, don't state any facts that are not true. Smartmarket is one of the most safest choices if you want to buy votes - in contrast to most upvote-bots, which are easily overbidden.
But you are free to use any bot you like.
Facts that are not true are not facts. Just saying.