One Word to summarize this section: "Consistency"
Let me tell you: this word will encompass near every use case Figma's team discussed
Why consistency?
For part of my user interfaces class, I had the chance to read Figma's design systems team's guide to good design for a UI -- typically a website, and while they had different advice for different things such as how to structure your grids or how you should handle your fonts, the one thing that appeared CONSISTENT throughout the entire set of articles was the push for set design standards and an understaning of what your webpages should look like. When things look like they don't belong, it makes your users suspicious. If they are suspicious, the lose faith in you and your website and they often do not come back. Have a clear idea of what the spacing between rows will be, what your agreed-upon font and typography choices are. If you pick something, stick with it -- don't have each developer come up with their own similar solution to an already solved problem. Consistency consistency consistency!
Credit
https://www.designsystems.com/space-grids-and-layouts/
https://www.designsystems.com/typography-guides/
https://www.designsystems.com/how-a-small-team-built-figma-dot-coms-design-system/
https://www.designsystems.com/guide-to-content-strategy-in-design-systems/