A form of personal and monetary control !
A large part of your earned Dirhams stay inside the country. The system is designed that way. Villas, shopping, schooling, entertainment for most part re-collect your income and recirculate it back to the same pockets it came from. Expats, for the large part sustain the UAE's economy, simply since they are the largest group. With a workforce of close to 1500 pilots together with their spouses and children (for most) you can see what a large impact this ultimately makes on the economical sustainability of Abu Dhabi.
On a personal level, to keep an eye on you and to allow a greater roster flexibility. More crews available with almost everyone living within an hour of base. Everything is negotiable here, including your rosters, thus anything to anywhere can be crewed within an hours notice.
I don't think commutability will ever be an option. They won't even allow you to live in Dubai anymore yet alone in another country.