Are retractable dog leashes safe?

Specialist training subreddits like r/Dogtraining and r/puppy101 (both high-trust communities in our signal mix) repeatedly warn that retractables offer limited control, can reinforce pulling, and the tape or handle can cause injury if it snaps back. They can work for trained dogs needing decompression sniff time on trails, but they're widely discouraged for puppies, strong pullers, or busy sidewalks.