This article is a bit late to the party. This has been an important concept in urban design for a long time now. Even before the sponge city concept was mainstream, people were creating similar projects.
Of course, in most cities they are too scattered to make a big difference. I can think of maybe a half dozen projects in this vein in my city which might take the edge off some local floods but it doesn’t solve the problem. As the article points out, you need to transform the landscape of much of the city to make it effective. In my view this will only be possible by removing significant car infrastructure.