If your students are like any and all readers (including you and me!) they find it challenging to read, recall, analyze, and then synthesize information from multiple sources.
As a reader, it takes a lot of focus and energy to process and comprehend one unfamiliar text, let alone two or more. Still, many of our students as young as third grade are being asked to read multiple, paired passages, comprehend, analyze, and then synthesize the information into a well-written short answer response (or!) longer essay/prompt.
While I admit this is an incredibly difficult task, I think it is one that is worthwhile for our students.