Engineers in the field rarely have physical copies of every standard. A PDF allows them to quickly reference torsional coefficients, load case equations, and example calculations on a laptop or tablet while inspecting an ageing crane or designing a modification.
Ignoring the guidelines set forth in DIN 15070 can lead to severe consequences. Din 15070 Pdf
You can obtain a copy of the DIN 15070 PDF document from: Engineers in the field rarely have physical copies