There's going to be a lot more Wikipedia articles with the explanatory note “ In this Japanese name, the family name is [surname].” If this catches on, maybe there will be three eras of Japanese name order in English. Pre-Meiji, Post-Meiji, Post-Reiwa.
This convention is widely practiced in Western journalism, but unfortunately it hasn't become common knowledge. As a Chinese person working in UK, I frequently have to explain my name order, despite the fact that most people have definitely seen "Eastern" names like Xi Jinping and Yao Ming in the news. I guess most people never asked themselves whether "Xi" and "Yao" are given names or family names.
Personally I welcome this change by the Japanese government. My hope is that this will raise awareness of the "Eastern" name order.