Well first let me separate science from engineering. Science is purely about knowledge, coming up with a small little bundle of facts that explain the world around us.
Engineering, medicine, etcetera are about applying this knowledge to make stuff happen.
That aside, some benefits of it are:
That it can help to convenience are lives (think of communication, these computers, mobiles and so on are all technology)
It can alleviate suffering (such as medical science)
It can give us purpose and understanding
Some bad things include:
It can give people access to dangerous information (such as how to harm people, do illegal trades etcetera)
It can cause suffering (such as the nuclear bombs did on Hiroshima and Nagasaki)
It can make life seem purposeless (such as apparently refuting the Bible etcetera)
