The domiciliary intent clause is there to prevent someone from claiming residency in Florida or the Reedy Creek Improvement District based on staying at a DVC resort. If someone could claim they are a resident based on staying at the DVC resort, they could claim what Disney would consider the most horrible thing in the world, the right to vote in the Reedy Creek elections, i.e., Florida's law protecting homeowners from debtors is likely secondary to that concern. Florida laws on residency are similar to residency laws elswhere and they all speak of intent to make a place your principal place of residency (often phrased in terms of "domicile') and you can establish such intent via such things as having stayed at a residence for some designated period of time, working in the state, having a driver's license in the state, having your kids enrolled in school in the state and other ways. However, any such intent to establish residency in Florida if the place you are claiming residency is the DVC resort is defeated by the clause in the declarations and that includes for any income tax purposes (although for the income tax benefit, all you need to establish is that you are not a resident of any other state and thus need not pay taxes in another state; you can be a US citizen and have no state residency; many living abroad have done just that; you do lose benefits doing that, e.g., you cannot get a state voting card to vote anywhere; your kids have no state college for in-state tuition).
You could, for example, separately rent an apartment in Florida, get a driver's license, get a job in Florida, and thus possibly become a resident even if you stay most of the time at the DVC resort but you cannot validly claim the DVC resort is your permanent residence or that staying there gives you any claim to being a resident. And I am speaking as a lawyer.