All religions I know of advocate that one should care and trust others. But "others" needs definition: in many cases it means others from the same religion, to the exclusion of other religions. Thus, if religiosity is higher, does this lead to higher social trust? It is not obvious as more religious people may trust more their own and less the others. To give a parallel in internation trade: are free trade unions good? Yes, because they reduce tariffs, but no if they increase tariffs for trade outside of the "club."
Niclas Bergren and Christian Bjørnskov study the religiosity and social trust question using survey data that, among others, asks to questions: "Is religion an important part of your daily life?" and "Can people in general be trusted?" They perform cross-country regressions using 105 countries and all US states. The outcome: reliogisity reduces social trust, both internationally and with the US states. Why? I can only speculate here, but humans are social beasts that operate at the level of clans. Religious affiliation is one expression of this. And for a religious person, anybody who does not share the same values is suspicious.
Does this mean the world would be better without religions? For one, less resources would be spent in demonstrating how my god is netter than yours. Also, this study shows that we would have more trust, an essentail ingredient of trade. But as Malthus said, I paraphrase, materialism is not the only element in happiness, spiritualism can be important, too.