I’ve never actually seen one (apart from on the shelf at Best Buy) but I assumed you could make them somewhat incognito.
I’d rather have something ring my phone compared to the obnoxious doorbell I have in my flat right now. I realise I could just buy and install a less obnoxious doorbell, but if I have to go to all that effort I’d like to replace it with tech 
- ideally something with an API.