Well, most of the time if I do resteem a content, it is usually for my references rather than just to let others see it.
Those bots that "offers resteeming services" is just bull because these are just "vote-for-vote" desperate "marketing" just to get you to send some steem / SBD over.
Even with upvote bots, as you have mentioned, does require heavy engagement. But how many out there do have enough time and energy to truly read and leave a thoughtful comment?
Now that's a good question.
And by the way, to get your post read from resteemed contents, I believe, personally, the title is very IMPORTANT.
Cheers!
@littlenewthings / @dses initiate