Currently fonts are only included in the back-up zip file if they had been rasterised in the project.
Igor has always maintained that rasterising is no longer necessary. However, if you will be working on another computer (someone else's) you are not guaranteed that your existing fonts will be replicated if they don't exist on the other computer.
Some design programs do pack all the components including fonts used in their back-up zip. Hence the suggestion that the new version does that too. Then the need for rasterising can be buried for ever.
Roel