I have often thought that phones could benefit from good old clicky buttons on them. There are many situations where it would be great to reach into your pocket/purse and cause an event of some kind without having to lug out the phone, enter PIN to unlock, bring up app, etc. etc.
- medic alert for seniors (notify caregivers)
- skip to next music track (e.g. when casting spotify to some other device)
- dial 911 when walking through a dodgy area
- count passengers embarking
- confirm visual check of some physical asset is OK (e.g. pest trap)
Thanks to the Jobs-ian design of modern devices, which emphasises style and coolness over usability in the real world (right mouse click anyone?), smartphones are not at all suited for these super rapid one click use cases, and adding nice clicky button(s) on the phone or a paired bluetooth device would be useful in many situations.
(Yes, perhaps we could buy an apple watch instead - but that's cracking a nut with a sledgehammer).