Why is zakat not obligatory on a residential house, while it is obligatory on money saved for the first time to buy a house for residence, knowing that it is preferable not to pay zakat on the former?

Zakat is obligatory on specific types of wealth: gold and silver (and banknotes, and what complements them from trade goods), livestock, produce from the earth (crops, fruits, and buried treasure/minerals), and trade goods. Zakat is not obligatory on personal assets (items acquired for personal use, not for trade), such as a home or a car, even if their value reaches millions; this is because they are not intended for growth. Zakat was legislated on growing wealth to make it easy for the Muslim, as it is paid from the growth of the wealth.