一、语义不同
be beneficial for
翻译：对某些事情有益处。
例句：It can be beneficial to share your feelings with someone you trust。
向自己信任的人倾诉感情是很有益处的。
be beneficial to
翻译：对某些人有好处。
例句：financial investments can also be beneficial to the society.
金融投资对社会也是有利的。
二、文法不同
be beneficial for 属于宾补，就是宾语补足语，是用来补充说明宾语。
例句：Relaxation classes can be beneficial to people of all ages.
放松课程对每个年龄段都是有益的。
be beneficial to 属于主补，就是主语补足语，用来补充说明主语。
例句：I think it would be beneficial for each committee member to have a copy of the report.
我认为给参会者每人一份报告的副本是有益的。
三、语境不同
be beneficial for 只能使用for的情况：be beneficial for somebody to do sth。
例句：Second, cooperation should be beneficial for Angola to grasp advanced technology.
二是合作应有利于安哥拉掌握先进的技术。
be beneficial to 属于标准搭配。
例句：It will be beneficial to all parties concerned. 这将会对所有有关的党派有益。