The thing that locals do know a lot of the time, is the spots that are actually great but not hyped up by influencers/social media, the cool spots that are often good by virtue of not being well known, etc. And no one is arguing that the locals know all the best cultural attractions, the point of asking locals for advice is to understand what they see in their own city.
This is where platforms like Couchers.org or whatever come up, where you want to actually understand the locals, more than just see the hyped up touristy stuff (which often can also be phenomenal!).
