I want to be able to hit Command+Plus and scale up the whole interface for presenting something to the team or when I have to code pair with someone who doesn't have as large of a monitor as I do.
Presentation mode is an absolute mess, and does not help with code pairing or code review presentations, and font scaling only affects the one file and not all the fonts, so the project navigation is still small and I have to repeat it for every file and again in reverse to reset it.
And the best past is, they could do it without impacting anyone else who doesn't need it, unlike this proposal.