I also think 50ms is a bit pessimistic, but there are locations which are far off of googles datacenters (at least until they finish their Johannesburg location, south africa seems very isolated) and you’re never directly connected via as-the-bird-flies fibre connections, actual path length will be longer than just drawing a line on a map.
This can all be mitigated by just building more and closer edge servers, of course, but at some point you just have a computer in your room again.