According to Muslims, yes. It's dubious how much benefit the conquests actually brought considering this vast empire in your pic didn't last very long, and the people there were soon at war with one another again, this time over dynastic and sectarian reasons rather than old geopolitical causes or tribal feuds (though these would inform the new factions, as with the Persian resurgence, and Berber rebellions in the west, among others).You could claim that Muslim "unity" for as long as it existed fostered trade and learning, and there is some truth to that. Some parts of the Caliphate, like Persia or Egypt, had already been very wealthy and had an educated populace before Islam, and many of the ancient cities in Africa and the Levant had histories of trade and sophistication, and it was only recent history that put them in a low state (the collapse of western Rome, the interminable wars between Byzantium and Persia). Muslims certainly believed they were doing good, though. Even when the caliphate splintered, there was a sense of there being a "muslim world" which was enlightened and prosperous, and a barbaric, debased "outside world".
>>18475673They was doing it under a just cause under their eyes
>>18475673Considering their only reason was that they wanted to conquer, no. For the non-Arabs living under them? Absolutely not. Civic culture ended under the Arabs, taxation increased to the point where the rate of taxation in places like Egypt in the 8th century were as high, or even higher than previous Roman taxation in the region. Local religion was universally persecuted and locals were barred from all power. The only real winners were the Arabs, who carved out the former empires into clan and tribal fiefdoms to tax farm for themselves.
>>18475673Thus in nature a lion tears apart an antelope not because it is "bad", but because such is the grand, dynamic and beautiful order of creation. So it is in the human world, Muslims were a powerful new civilization, they conquered other civilizations that were dying and dying to create their own grand new civilization.
>>18475673Justifying conquests is gay, next question
>>18475673RATIONALIZED, NOT JUSTIFIED.ISLAMISM IS FUNDAMENTALLY UNJUST, SINCE IT IS HERETICAL; ALL HERETICAL SECTS STRIVE AGAINST TRUTH, THEREFORE ALL HERETICAL SECTS ARE FALLACIOUS; THAT WHICH IS FALSE IS NOT JUST.