Individual and community health issues aside, boiling water over wood or charcoal stoves has enormous consequences for the planet’s climate.
The use of wood or charcoal contributes to climate change by producing high levels of greenhouse gases. Further, it destroys forests, resulting in more rapid rainfall runoff and water scarcity.
Using UV to sterilize water (which is what the waterbox does) is more than 1500 times as energy efficient as boiling.
Even if you could somehow use a stove to power the waterbox, the energy efficiency of the germicidal flourescent light in the waterbox would only produce 0.06% of greenhouse gases compared to boiling over charcoal or wood.