One thing did (https://www.kickstarter.com/projects/800343142/tylt-vu-pulse...), and unfortunately Pebble just kind of screwed them over. I can't imagine there's any malice involved; integrating HR was an obvious step forward for the product. Backers got an update today advising us that Pebble and Tylt have collaborated such that the Pulse will be able to feed HR data to Pebble Health, so it looks like Pebble have probably been good to deal with.
Still, I imagine it leaves a sour taste in the mouth of anyone else looking at making "Smart Straps".
Looking at the back, it appears so. I think they've sort of backed off on the Smart Strap strategy after nothing has really materialized out of it.