Yes, they can. Because they are based on real events, they carry a certain weight of truth. For example, 'The Diary of a Young Girl' by Anne Frank. It's a true account of her life in hiding during the Holocaust. Readers can feel the real fear, hope and struggle, which makes it more impactful than many fictional stories.
It depends on various factors. However, books based on a true story often have the advantage of authenticity. They can expose readers to real social issues, historical events, etc. For example, books about civil rights movements based on true stories can make readers understand the real struggle and progress better. But fictional books can also be very impactful with their creativity and imagination. So it's not always a clear - cut answer.
In some ways, they can be more impactful. A book based on a true story can give readers a direct connection to real - world events or people. For instance, 'Into Thin Air' which tells about a real mountaineering disaster. The real - life details and the fact that it actually happened make it more poignant and impactful. Fiction has its charm, but true - story books have the power of authenticity.