There are at least as many reasons to obtain a second passport as there are passports, but only two of them are fundamental:
The technological advances, cheap intercontinental flights, the proliferation of English and the convergence of popular culture of the last several decades have swept away many of the barriers that once kept the peoples of the world apart.
Travel and settlement restrictions, stemming from a time when most were monolingual and never left their homelands, are an anachronism in an era where individual identity is increasingly separate from nationality. For those who have the means, there’s no longer any reason to accept the limitations of borders.
Countries with CIPs share two common features:
Dual citizenship is liberty. It’s the liberty to travel, work, study and settle where you please – when you please. It’s the liberty to pursue investment opportunities regardless of location and to pay a rate of taxation that’s acceptable to you.