The notion that the world would be better off without any religion is neither new nor uncommon, especially among certain non-religious communities such as "New Atheists." However, for the reasons I will list in this thread, I believe it is inaccurate and largely incorrect in that it seems to view and treat religious belief as somehow inherently different from other cultural, ideological, and political views that can influence one's actions.
- During multiple periods in history, religious belief that the universe is the creation of a deity has been behind a considerable amount of scientific and philosophical thought. This extends from medieval periods of Christian dominance over Europe to the Islamic Golden Age, when the natural sciences were viewed by some thinkers and scientists as a way to understand God's creation.
- Religious thought around the world has given humanity some immensely useful concepts or at least helped to popularize and widen their use. These include meditation, mindfulness, literary and textual analysis (especially to understand scripture), and poetic and linguistic devices that have made their way into various literary and artistic media.
Qur'anic Arabic greatly influences a lot of Arabic poetry, for instance, and Dante's Inferno is another example of an outstanding artistic contribution influenced by religious concepts and thought.
- The sense of community that religions offer has an undeniably positive outcome for the lives of many people. Humans are social creatures, and it is no surprise that a venue for bonding and connecting over deeply held beliefs is valuable for many of them.
- Due to some religions' emphasis on the value of charity and giving to the poor, many in need have benefited from aid given by religious institutions, especially when state apparatuses meant to oversee social security have failed or functioned improperly. The Catholic Church, for all of its faults, has helped a lot of poor people throughout its history, as have many mosques and Islamic community centers, among others.
This is a very brief list, but the main point is that, in my opinion, the world wouldn't be any better or worse off without religion than it would be without, say, politics or other cultural elements. We can see that political ideology underpins hatred, persecution, and tribalism in countries like China and North Korea regardless of religious affiliation. As with any human institution, politics, religion, and culture all have their pros and cons, and I don't believe religion is so unique in this regard as to render its absence from the world a necessarily good thing on the whole.