What are the issues by converting Hijri (Islamic) calendar into Gregorian?
About the same as the old Chinese calendar, which is still used for many things in China. Islamic countries use the Hijri for religious purposes but use the Gregorian in everyday business, etc., as does the rest of the world. It is no different from the international time system. This was established back in the seventeenth century by the British, because they were the greatest mercantile and shipping nation in the world at the time. Greenwich Mean Time (‘Zulu’ in military and air/sea traffic terminology) is purely arbitrary. But it is so established that we continue to use it.
