For the record, I got a 0.95$ (it was 0.05$ before you voted and 1$ after) on a 0.5 SBD bid.
Minnowbooster guarantees a 2.75 times return, and all of these values are not real, because SBD is treated as 1$ by the Steem rewards system, whereas in reality it is at 2.41$ while I am typing this.
It means that 1/2 of the rewards are in fact worth 2.41 times as much as they seem, but the entire payment itself is worth 2.41 times as much.
In my case it means the reward is worth 0.47+0.47*2.41=1.6$ , whereas my bid is worth 1.2$, so yes, it is a positive ROI in this case too, due to the recent further decline in SBD price.
While I admit most other bots deliver an even worse ROI than this bot, I also encountered better ROIs by some bidbots that are scams.
Since I mentioned minnowbooster, I recently encountered an extreme case of scamming by them, relative to the size of the bid, so they are not necessarily better than you, but most of the time they are.
I brought these reservations, because all of this is for the record.