I start all my UI projects with this principle, but it's extremely difficult to maintain as screens evolve. I want typography-driven interfaces with structure communicated through headings and spatial grouping, but I usually end up with far more borders and nested padding than I think is "right" as I run into the limits of whitespace as an organizing structure, particularly when the audience has a limited attention span or time to engage.
From experience, borders/cards help communicate conceptual boundaries, while whitespace helps communicate information hierarchy - Gestalt principles don't really address that distinction. For product or data-driven UI where a lot of loosely-related information/topics are shown in discrete parts of the page, cards are effective at high-level grouping. For content-driven UI, whitespace can be sufficient, and I think the article makes this clear.
Other than 'The Ultimate Developer Toolkit' (where type size is more of an issue than the card layout), I actually think the card-based version of each example layout is more compelling - easier to scan, and easier to 'chunk' - despite wanting the typography-and-whitespace alternative to be sufficient.
From experience, borders/cards help communicate conceptual boundaries, while whitespace helps communicate information hierarchy - Gestalt principles don't really address that distinction. For product or data-driven UI where a lot of loosely-related information/topics are shown in discrete parts of the page, cards are effective at high-level grouping. For content-driven UI, whitespace can be sufficient, and I think the article makes this clear.
Other than 'The Ultimate Developer Toolkit' (where type size is more of an issue than the card layout), I actually think the card-based version of each example layout is more compelling - easier to scan, and easier to 'chunk' - despite wanting the typography-and-whitespace alternative to be sufficient.