It's less of an issue for visualisations, as if a designer creates a mock-up, it's only used as a guide for implementation by a programmer, rather than an actua

It's less of an issue for visualisations, as if a designer creates a mock-up, it's only used as a guide for implementation by a programmer, rather than an actual asset. However we have used Sketch's SVG export for things like icons, and I've found it to be pretty good. There's even an CLI export tool than you can integrate into your build process.