Not always.

Having done this a fair bit, I've often found that if I have a somewhat minimal template (perhaps haven't gotten to the design stage of a talk and I'm just fleshing out the content of the slides), it's far slower to fire up a GUI and make 50-odd slides than it is to write a Markdown document.

Example:

---

#This is a headline

##This is my subhead.

* And * Some * bullets

---

That took me 14 seconds. Creating a new slide, 3 textboxes, and adding in the text in a GUI would take me significantly longer. And that multiplies up for each slide.

That's particularly true if I'm having to produce a lot of similar slideshows, for an extended course or something similar.

In that case, Markdown -> Powerpoint or similar tools are an absolute godsend.

Simplest answer for me would be the ability to use effective version control for slides.

Perhaps you have existing MD notes that you would like to quickly reuse as slides?

Perhaps your workflow is MD based and you want a way to target Google Slides as an output in addition to the other targets that you already have?

- Conversion to multiple formats, not just slides. E.g., making slides out of this org file was a single command: https://github.com/coventry/tfintro/blob/master/notes.org

- Accessibility via whatever text editor you're already familiar with

- Legible diffs in version control

- Text processing is easy to script

Thanks for the replies - I guess just because I don't find something useful doesn't mean that others wont - its always nice to have additional tools

Going to have to chime in that I recently tried making slides in Google Docs and found the experience absolutely horrible. Trying to add numbered bullet points, and expecting it to be a formatting option as in normal Google Docs, was particularly annoying.

Automation could be one reason. For example you might have a weekly meeting and wish to show some relevant metrics and graphs updated for every week, then you could generate such a set of slides using a script triggered by cron.