How should AI voice features in Gmail and Docs be measured?

Voice is useful when typing is the bottleneck, but a clean transcript is not the finish line. For Gmail and Docs, compare a week of similar messages or drafts made by voice and keyboard: time to a ready-to-send version, edits to names, dates, and commitments, recipient follow-up questions, and anything corrected after sending. Fewer keystrokes do not help if somebody still has to translate a muddled draft before it can leave the building. What would you measure first?