I have still somehow struggle to do this properly consistently over the years. I feel like you're downplaying a real common household issue that people have.
If this automation was cheaper/easier then there might be a real product here. I have seen self-watering pots in stores but they were far too expensive and not adaptable to any plant/pot.
I may look into this DIY solution as a side-project myself...
Having strangers on the internet deciding whether or not to water your plant is a wonderful social experiment, though!
This might get way to dark way too fast :)
What if you connected it to solar panels? Surely that would make it easier. And put a lamp above the solar panels just in case the plant needs watering at night.