The markdown to presentation approach is great. You can manage your slide (or slips) as code giving you history, offline collaboration, pull requests, etc. I don't think you can do that with most other presentation tools. I've used Marp [1] for traditional slides, and wrote a GitHub template repo that outputs the Marp HTML to GitHub Pages [2]. Similar workflows should be possible for Slipshow.
I see a huge markdown fan! I'm on the same page! We're building an entire ecosystem for markdown slides for the same reason.
The same design for all slides in the same workspace, a hosted version for non-developers, each slide has its own public url for easy slide playback, and more ...
Try if you are interested in slidepicker.com (beta)
I've wanted to love MARP for years but the documentation is so limited (and tutorials so sparse) that building a presentation with any complexity beyond the basics is almost impossible unless you have a solid understanding of CSS and YAML front matter.
It's a shame, because I think the idea of MARP is revolutionary, but in practice PowerPoint (or even free alternatives like Google Slides) is easier to use.
Having modifiable source inside the html is a great idea. I'll still need to have a compile workflow to add image while keeping a standalone produced html file (and some other feature such as live-preview), but I'll definitely add this as a possible workflow.
Thanks for the link, and the idea! Definitely a github action to automatically publish your Slipshow presentation on push would be a great workflow! (I'll open an issue for that!)
Also, Quarto to reveal.js is an amazing pipeline, and ties in well with the rest of the Quarto ecosystem meaning that you can reuse content from other mediums more easily.
[1] https://marp.app/
[2] https://github.com/ralexander-phi/marp-to-pages