Of course they are useless. A little common sense. First off the followers are 99% fake. Second, even if somehow they managed to get that many real followers (highly doubtful unless they are celebrities in their own right/but then they would not be selling gigs on Fiverr), those followers would be sick to death of all the crap these guys were tweeting about and pushing right. Save your money, you'll get no traffic. A social signal boost for your SEO endeavors maybe, but not even worth $5