The residency requirement is that minimum. It's not a minimum in monetary limits. It's a minimum that you have to actually live there. The fact you are living there means you are paying a higher tax amount than for an undeveloped lot. There's a difference on having a house on a lot vs just some field. You have some skin in the game as they say compared to just owning land while living somewhere else completely.

What if you lived in a tent in the field?