What are the pros and cons of the Crusades?

The Crusades were notable for their particular cruelty and massacres. These were long and bloody wars that claimed the lives of hundreds of thousands of people. Such campaigns under the guise of “good for the sake of religion” often had a political and predatory motive.

For whom were the benefits of the Crusades? Obviously not to the common people, but only to the rulers of that time. Having captured the next “rebellious” people, they seized more and more territories and increased their influence on the world arena of that time, often elevating themselves to the rank of “saints”.