Spanner is literally a Google cloud product you can buy ignoring that it underpins a good amount of Google tech internally. The same is true of other stuff. Dismissing it as a recruitment tool indicates you haven’t worked at Google or really know much about their product lines.
More people see the blog posts as it’s a more gentle introduction than the paper itself. Sure it might generate interest in Google but it also generates interest for people to further look into the research. They are not for sales of the tech but I’m not sure the impact is just a recruitment tool even if that’s how Google justified the work to itself.
