How many new users have those services brought to Steem? None...
How do they help Steem grow? They don't....
They are one of the biggest problems Steem has at the moment and nobody even sees it...
I believe that incredibly misguided thinking such as this is one of the biggest problems Steem has at the moment.
I personally have brought quite a few investors into the Steem platform who have invested over one hundred thousand dollars (and hopefully a lot more in the near future) specifically for the opportunity of investing their Steem into a voting a bot.
Additionally, voting bots provide a very valuable service to authors. I know because they are what gave me the start i needed on the platform. If it wasn't for voting bots I probably would not be here right now.
Voting bots provide a valuable service to users and actively attract investors to the platform (I'm literally meeting with a crypto fund this evening to present this opportunity). Find me anything else on here that can claim that!
Please look a little more carefully next time before claiming that content promotion services don't bring new users to Steem or help Steem grow, because in reality they do a great job of both of those things!