Earlier quoted context omitted.
I was wondering why not use SVG (or any other vector file format) files and render all the graphic on the device, instead of including tons of PNG at various resolutions.
Because the experience is subpar when that is done. It is impossible to create a vector image that will result in clean, unblurred strokes at arbitrary small pixel sizes. Don't even suggest using TrueType-style hinting, I don't think any designer would want to touch that with a 10 foot pole.
eg png is fine, but if a developer wants to include svg then let them.
For developers who do care about the clean, unblurred stroked at arbitrary pixel sizes this wouldn't impact them at all.
For the developers who care more about the space taken up, this would give them a potential useful option.