I’m using the button for something super-simple - my app is a combo product catalog and business card (on steroids, thank you Glide) - so I just made a floating “call me” button - click and you can instantly connect. At least with my Google Voice number 
This is a great addition to my app! Also, I added a large empty divider at the bottom of my app so someone can scroll completely past the button to view all text.
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