This does assume that scrapers are smart, and often they're really not. They have infrastructure for scraping HTML from webpages at scale and that is the hammer they use for all nails. (e.g. Wikipedia has to fight off scraper traffic despite full archives being available as torrents, etc.)

In this case I agree though, they're all spammers and/or "clout farmers", or trying to make an account seem more authentic for future scams. They want to generate follow notifications in the hope that some will follow them back (and if they don't, they unfollow again after some interval).