Brilliant post lol it absolutely deserves attention and response! People are bound to find new uses we've never thought of and just like you said, I would encourage them to put here whatever they've come up with.
In the mean time, I will list a whole bunch of ideas that we have thought over time and I'm sure I'm forgetting some too as I'm going by memory..

• Door or window alarm - put it next to a magnet (not all magnets are strong enough to work, but many do) and when it separates it will power on and send a message that you pre-made (eg; front door opened!)

• If you have an Android device, you can pre-record a VSMS (that's a voice short message) - say anything you want, I love you! or Help I'm in trouble! and when you press the SiB it will ring a phone (any phone) and play that message back 3 times. If you have an iOS device, this feature is not currently available (Feb 29, 2020) but will be in our next release that's coming out in just a few days.

• If you have a clear SiB (ideally) you can use it as a night light! - just program the LED to stay on for x amount of seconds or minutes and to power off automatically after..
  A program for that would look like:
  Prog S
  Hold wd 3 1
  Hold wd 18 1
  Hold wd 23 1
  Sl 30s
  Off
  
  Prog S: means 1 short click to turn on program
  Wd 3, 18 and 23 are digital pins that control the LED and 1 = ON in this case (not always) and 0 = off.
  Hold ensures the pin remains on even when the CPU is sleeping to preserve battery.
  SL stands for "sleep" - tells the CPU to go to sleep in this case for 30 seconds.
  When the SiB wakes from sleep after 30s of having the LED full on, it see the OFF command to power off.
  
  The above program just came to mind as a use, but its not available on the app section of config your SiB, so we'll add it there in the near future so programming is not necessary.

• We have the "sweet dreams" program of course which pulsates through the light to help you go to sleep - more info on this can be found on how NASA put their Astronauts to sleep using light on Google (RED is best, but watching the lights pulsate on the roof of your bedroom at night in any color is fun) - once again, clear SiB is best for this.

• Do you need to be reminded about anything at all at a certain time of the day? - you can program the SiB to wake and blink for X amount of time and when pressed it will go to sleep OR if not pressed within that amount of time it can send you a reminder message!

• Have you or a family member ever forgot to close the door of your fridge or freezer? you can put a SiB to monitor the temperature and if it notices the temp has risen beyond its setting, it will send you a message. The battery life is reduced when in very cold temperatures, but you should still get about a year or more out of it.

• Door bell as you mentioned is another

• If you have an elderly parent and want to keep tabs on them, why not gift them a SiB? - you could even put it on the door of their fridge with a magnet (or a motion sensor accessory when ready) and if the door is opened at least once a day, the SiB is happy and sleeps. But if the fridge door is not opened within whatever time frame you've set it to, it will wake and send a message to you or anybody else you've included in the contacts.

• Of course, they could just gift them a SiB to keep anywhere they frequent and in case they need you, its just a quick press.

The list will grow and I can think of another bunch of uses that are either currently in experimental phase or/and will become available as soon as we start tapping into the Bluetooth features of the SiB.

For example it could be used as a proximity sensor when its near your phone, leave it under your bike seat (if you're close to it but not paying attention), or in a bag and if somebody takes it, you'd be instantly alerted on your mobile.
It can sense your presence as you enter a room and turn on the lights or carry out any other tasks.
When on your pet, if your pet escapes, the BT would turn on and provide critical information to somebody that finds the pet, such as owner's name, address, phone etc.
Leave it in your car to replace garage remote control. When pressed it would communicate with your mobile, your mobile would then send a message to another SiB that controls the opening and closing of your garage door - much quicker and safer than opening an app to activate this as you're driving away or towards it. Also, because its paired to your mobile only, if somebody steals it from your car, your house remains safe unlike a normal garage door opener that in the wrong hands will expose your entire home.

As we come up with more ideas, I'll add them here, but in the mean time, thank you for your initiative!

Any chance of an Alexa integration soon? My simp has been on a shelf since I got it, haven't had any uses.  Really would like this to integrate as a trigger for smart home functions.