Apple Watch - Sharing your heartbeat

The Apple Watch is set to hit stores in April, and there's been lots of speculation of what your favourite apps will look like, and what use it will be. I've previously written about how the Apple Health app seems to automagically count your steps, and I think this will be very useful on the watch as you (presumably) have your watch more than your phone, providing a more accurate representation of your steps (presuming most people don't pick up their phone every time they walk to the toilet / printer / water cooler in the office). 

What I want to speculate on is how people may use the heartbeat sharing feature - what possible use cases do users have for this? I can think of a few that may be used, so perhaps this feature is nothing to scoff at. 

1. Exercise buddies. 
Let's say Kayla and Veronica have decided to bolster each others health kick. They might not always be physically together when they are exercising, but sharing of their heartbeats could let the other know they are exercising, and perhaps motivate the other to schedule in some later.  

2. Communicate simply without words. 
If someone gives Kayla some exciting news, and Kayla can't reply maybe she briefly sends her elevated heartbeat to communicate excitement without requiring much interaction. I could see this being used for all sorts of subtle communication - boredom, excitement, fear, arousal, all without having to interact with the watch very much.

3. Sexting. 
I don't want to go into this one, but this seems like an obvious use case. 


4. Let someone know you're thinking of them.
Remember Yo!? Yo was an app that let you send a simple message (literally yo) to people so they could know you were thinking of them. What nicer way to let someone know that you're thinking of them than sharing your heartbeat? Especially in the case of romantic love, it seems quite endearing.

Or perhaps the guys at Apple are just huge fans of the cartoon Pon and Zi (If I can't hear your heartbeat, you're too far away") or HelloGoodbye lyrics ("you can't be close enough unless I'm feeling your heart beat")

What other use cases can you think of for sharing your heartbeat using the Apple Watch?