Disclaimer: I'm an older dev out of the game. I could definitely see the bigger picture faster than I could type it (except for challenging tasks), but that typing time was also synergistic thinking time. Not unfrequently, I'd find a better design while writing the code. Even if it didn't make it into that codebase, it could be filed away for future reference.

Edit: I recall reading somewhere that John Carmack doesn't care about which editor he uses because typing was never the bottleneck. Admittedly, he worked on some really difficult problems.