Their accountant recommends that they buy a home because they can use the tax break. Other restrictions apply, but for most homeowners this deduction provides a significant tax savings.
Property taxes paid on a primary residence are also tax-deductible.
There are other benefits to owning your home like pride of ownership and the security of knowing that a landlord can't force you to move at the end of your lease. You can decorate and remodel without having to ask a landlord for permission. Part of each mortgage payment goes to pay back principal. This is the equivalent of an enforced savings plan. And, if prices rise between the time that you buy and sell your home, you earn appreciation.