Worst smartphone gimmick?

I have seen a lot of stupid stuff on smartphones over the years. The flex in LG Flex, the Facebook button on the HTC Social, etc. But after seeing the GS5 at MWC I think the heart monitor takes the cake. How often are people going to use it? Are Americans all of a sudden concerned for their heart health? If so, buy an activity monitor. What do you think of this feature? Also what is the stupidest gimmick you have seen on a smartphone?