Not everyone lives in a cityscape hellhole so we are going to need higher speeds to be able to not suck up people’s free time just to be able to get within range of a job without living in a sardine can apartment complex.
Not everyone can live within 1 mile of their job, and travel via bike – nor does everyone want to.
If you’re going to limit everyone and everything to 5mph, then you need an alternative that provides a quicker means of travel in rural/suburban areas.