Margin breaks component encapsulation. A well-built component should not affect anything outside itself.

Adam Argyle wrote slightly earlier that he predicted the usage of margin to naturally decline:

Prediction: margins in stylesheets will decline as gap in stylesheets climb

Well it’s four years later now! Has any of this played out? Well it’s super hard to know. Anecdotally, it feels like gap is much more heavily used and my own usage is certainly up. There is public data on usage of CSS features, and, amazingly, margin usage does appear to be slowly going down.

I say “amazingly” because the way this data is collected checks if the site uses the feature at all, not how much it’s used.

The chart below shows the percentage of page loads (in Chrome) that use this feature at least once.

So seeing a dip here means less sites are using the margin properly entirely.