"Green at the same time" in the UK is flashing-amber and means "if free, proceed with caution".
Nearby, in a shopping/student district, there is a dual-carriage-away with high pedestrian crossing flow. It is only green for pedestrians for a few seconds before going to flashing-amber for both. It makes some sense as it's so wide that many cars can pass while people are still crossing.
However, as a pedestrian, I really hate it and feel unsafe. It rewards driver aggression because they treat it as green try to intimidate pedestrians by racing at any that are crossing or thinking about it.
Ultimately I think it angers both parties because each one thinks they have right of way and the other party is in error when really the flashing-amber has made it ambiguous and turns it into "aggressor wins".