I personally use the promo bots to gain followers. I have been posting on Steemit since the beginning - but i've taken breaks in between. It is a terrible financial proposition but it helps build a following and re-establish old connections. A backlink from this site is valuable and I dont think its wrong if relevant to the article.
Some of those spam links are competitors trying to poison your competion. Most companies have a huge disavow list - some of those links might be on it.
Like medium or buzzfeed or any other site that allows user contribution - it will always (and should always) be a part of SEO. I don't think google will ever reach the point where it simply looks at quality content - it will evolve -but as long as they are the gatekeepers setting the rules - we'll shape our content strategy to follow suit! Good luck with your SEO endeavors!