* Presentations can be exported as PDF.
* Presentations can be downloaded as a single stand-alone HTML file for offline presentation.
* Presentations can be imported/exported from/to Powerpoint.
* Collaborative editing.
TBH HTML isn't a really good format for stuff like this, as HTML is text-only. Same goes for HAR. The moment you want to embed large images/video you run into size problems.
It would be really nice if browsers supported some kind of archive that contains multiple resources like images, wasm files, etc, that would all be accessible by the browser if you open it. file protocol is basically being deprecated by chrome for stupid security reasons: https://github.com/WebAssembly/design/issues/1200
Is this really a problem for up to 100 MB? In my experience that would already be a huge Powerpoint presentation including a lot of detailed images or some smaller videos. Most presentations I handle are below 100 slides and below 10 MB.
If it goes beyond that, there will also be other problems. Nobody likes to handle a 5 GB presentation.
Encoding the binary files as BASE64 would add some overhead, indeed, but having a presentation as a single file that can be played by any modern browser on any modern device would provide tremendous usability benefits.
There is a patch coming in the new year with real time colab, export to PPT, local presentation modes and quite a few more features
The paradox here is that the better the export functionality works the less people will actually need it.