Arabic script is closely associated with Islam. Holy Quran must be read in Arabic thus people who converted into Islam learned the language and the script. It is thus used to write the languages of most muslim nations.
The cities at the Gulf have been completely transformed in the recent decades on the oil wealth. Before the oil extraction began ~1970s all of them were small insignificant desert outposts. Since then the population of Gulf cities imploded 10 to 40 times, doubling every decade or so.