It has to do with reach - billboards are typically high-volume, low-specificity ...

bduerst on Sept 6, 2018 | parent | context | favorite | on: Google wants websites to adopt AMP as the default ...

It has to do with reach - billboards are typically high-volume, low-specificity impressions while placards and banners are typically event-specific and have a lower, more targeted audiences. There's gray area, obviously, like billboards in airports.