If you garden then you may want to know your actual amount of rainfall to gauge how much watering you need to do. You'd be surprised how much rainfall can actually vary over a small area compared to a regional average.
And for people in rural areas that are not near other weather sensors, or areas that may not have regular internet connectivity or frequent outages (and coastal areas subject to storms and high winds). And of course weather nerds and sensor nerds, because those MQTT databases won't fill themselves.
Yes, growing crops. The hyper local weather has been drastically different the last few years (dry; redwoods are stressed, etc).
Also, there is no vaguely-accurate local weather station for our place (internet services report wind speeds and temps that are routinely off by 20% / 10 degrees F, and rainfall that is off by 5x)
They're good, too. Accurate and good battery life.
I have mine feeding to Ambient Weather, but also a custom API endpoint that feeds the data into a local database, so I can use my own software/scripts to do as I please without having to make external API calls.