I've considered preprocessing but many of these devices are connectible and you can't download SVGs if I don't support them. I don't know how big of a deal that is in practice, probably not much, but it would actually be a lot more work for me. I have codebases I'm pulling from, mainly a nanosvg port I completed for gfx 1.0, and plutosvg so I have quite a bit of the work more or less done, waiting to import and massage. If I switch to another format I have to redo all that code. TinyVG is interesting, and I'll keep it in my back pocket, until I hear that someone's actually using the format, as this is the first I've heard of it. One of the advantages of htcw_gfx is you don't need to preprocess most things. You can get your screens directly from your designers in SVG, PNG or whatever, and simply put them on the display. This saves time, especially when you have a lot of assets. It also makes the build process simpler since you're not doing any preprocessing of assets. So all that said, I like being able to support formats as they were intended, where possible.
Check out my IoT graphics library here: https://honeythecodewitch.com/gfx And my IoT UI/User Experience library here: https://honeythecodewitch.com/uix