I've been wondering the same. I have a limited amount of SP but when I read a post about smartsteem yesterday and used their calculator I noticed I actually can get some return.
I've been reading over the pro's and con's of bots lately and I can't make my mind about them. On the one hand I understand the upside for small authors to get post promotion trough bots but on the other hand you start to lose the manual curation and the fact that people actually read content.
I think I gone sell some votes when my SP goes > 92% or sell for example 5 100% votes. . I can't curate daily so my voting power will have some good use and on the other hand I have enough SP left to curate manually when I want to.
I let go smartsteem. It is not worth losing the fun of steemit. I set my limit at 50% but they regularly dragged it down way further.