Sometimes it takes quite a lot time to grasp one new method (such as machine learning); on the other hand, you may just need less than half an hour to learn one skill. R Markdown is the latter one but change your way of working.
My experience of using R Markdown since 2006 for statistical analysis and reporting mainly focused on exploratory analysis. The reports generated were word/pdf/html documents. I have not worked on a real example of slides format yet (except simple demo with one or two slides).