Years ago, with a then-ubiquitous Moto flip phone at my hip, I "invented" what I called the "Urban Commando Phone" - the cell phone already had a clock, why not add things like flashlight, garage door remote, TV Universal Remote, etc. so that instead of having dozens of devices, you had one to "rule them all".
I had no idea, at the time, of the types of convergence that would come in the form of the smart phone, which has all of these and many more either available built in
or easily available.
The term "ubiquitous computing" has been used for decades, and when I first heard the term, it was to convey the still-radical idea that every home would have a computer.
Computing seems to come in stages or "generations", where each previous generation generally powers or enables the next one. Mainframes became infrastructure for Mini computers, which (eventually) gave way to PCs, which then merged with Mini computers in the Internet revolution, which then gave birth to the smart phone era.
Following this trend, the "next big thing" will use Cell phones, PCs, and Servers to extend their capability. And this is already happening. My cell phone has a small cluster of devices that surround it that it interfaces with: Bluetooth headset, folding mobile keyboard, smart watch, etc. We are just beginning to innovate with these standards-based technologies to develop the true "IoT" that is coming; the things that link to our mobile phones to enable things we haven't begun to imagine.
Some examples that I've seen/heard of include all manner of medical devices: insulin pumps that use software on your smart phone to adjust or recommend insulin administration. Devices that provide the ability to test for common diseases "in the field" inexpensively, serving field medics and impoverished areas alike. Payment systems that use our mobile phones and networks to augment or replace credit cards.
And on and on. As always, the game is just beginning!