but useful also是什么使用方法(表强调吗)

Perhaps all the deficiencies have since been rectified. It seems to me there are many things that the schools should teach — things that truly would be useful in later life, useful in making a stronger country and a better world, but useful also in making people happier. Human beings enjoy learning.

问题: but useful also in making people happier 这句话 useful 如何在 but also 中间，感觉是强调的使用方法吗？

感觉是强调的使用方法吗？——为何要凭感觉考虑问题？强调什么呢？

在but also...中，also 可以省略不需要，也可以与but 分开，放在句子的其他地方。看来网友还要加大英语阅读，如此的使用方法不是俯拾皆是吗？