Sometimes we do not want to show everything at once on a slide, but show the content incrementally. A most useful presentation trick is to hold certain surprises or funny GIFs until the last moment.
Today I spent a couple of hours on creating an example presentation based on xaringan and remark.js, which covered the three approaches to incremental slides. You can find the Markdown source document on the last slide. Hopefully it has illustrated the power as well as simplicity of remark.js.