So someone added SIP functionality (no mobile phone/cell phone/3g/... inbuilt, only wifi) and a battery to an ESP32 (new and possibly rapidly rising programmable chip, one of the few things I have seen in recent times that might one day sit alongside the arduino, pic microcontroller and raspberry pi in name recognition/market saturation) and think it is going to do things for people.
I could see some benefitting from it, indeed if it had even basic options to make mobile phone calls then my bomb making distributed fun would have little limit. As it stands I struggle to see why I would use this over said arduino, pi, pic chip, clones thereof or the like other than it coming as a full wifi enabled battery sporting thing out of the box. Minor options if you say wanted to control some custom setup (heating, audio, security, kitchen requests...) in a business with a phone wired into the complicated phone setup but most just have a tablet for that if they need it.
To that end back to looking at de googled phones.