I used to have a partner who was hearing impaired (H.I.).
There is a whole world of devices that are designed for the H.I.
And many of these features could be programmed into Smartthings, without adding new devices to your product stack, and adding some other features by adding some products.
Blink lights number of times, then return to previous state,
Blink lights a certain color, then return to previous state,
If front door button is pushed, blink "Lamp Plug" 2 times.
If back door opens, blink "light bulb" 3 times, green color.
If smoke detector is triggered, blink all lights until fire cleared, red color (if supported)
Bed-shakers /vibrator motors ( bed shakers exist, but are not smart, closed systems, blah blah google for more info)
If front door opens, short double vibrate couch shaker,
If Alarm clock is alarming, vibrate bed shaker, (this would require an alarm clock, or making a rule in google assistant to use a SmartThings device) But helpful.
If Samsung Dryer is done laundry, vibrate couch and blink lights yellow.
This is a market of people that are already doing these things with non-smart devices. These customers are yours, if you put in the smallest bit of programming into the app to blink lights. even more so if you make a smart-device for them.