The basic idea is simple: a government grants residency rights to foreigners who place a qualifying amount in housing. The qualifying amount differs greatly between countries, and governments change it with limited notice.
One key point separates residence and a passport. The permit lets you live there, usually subject to renewal, but a passport normally requires a long period of residence. A promise of nationality in return for an apartment purchase is reason for caution.
Beyond the purchase price, these schemes impose extra obligations. Frequent requirements involve proof of no criminal record, health cover, proof of income and a minimum stay in the country per year. Overlooking any of these can end the status even if the property is still yours.
Fiscal residency remains a different question altogether. Holding a residence permit does not by itself make you liable for local income tax, and living there olhao real estate for sale most of the year usually will. Many countries rely on a day-count rule, and the effects reach income earned elsewhere.
The realistic approach is straightforward: choose the buy property in barcelona first, and let the permit be the second reason. Programmes are suspended with limited notice, and a home selected purely for the status becomes hard to rent and hard to resell.