"no longer" implies that geoblocking was ever supported, suggested, or allowed. It has always been explicitly discouraged and unsupported. Many subscribers had issues prior to the new vantage points being deployed, because they did not expect their geoblocking would obviously impact any sort of domain validation.
Multi-perspective validation was designed to defend against security concerns that you unfortunately do not understand or fully comprehend. This topic has been discussed extensively and exhaustively on this forum. Here is a primer from the docs, and I suggest you search the forum for more information as there have been many nearly-identical posts here in the past - one of which in the past few weeks.