Even at "only" 15mph, riding brakeless and foot retentionless can be risky for an inexperienced FG rider, especially on busy streets. I've done all that at some time or other, but then I've been riding / racing FG bikes for 35 years. All things considered, I'd recommend at least starting out with both a front brake and some sort of foot retention when riding on the street. By choice, I do both anyway.