After reviewing the manufactures general installation instructions, I would think that these nails would meet the requirements for this application.
A confusing situation. Joist hangers are usually hung on 1 1/2" thick framing material. Therefore you only want 1 1/2" in length, but the diameter is the same as a normal 8d galvanized nail. You are correct, but the description for these nails needs to be such that you know the diameter and what it will fit. "d' or penny is the common trade nomenclature that is now used more for the diameter, in turn, an indirect reference to shear strength. Before the short hanger nails were made, the 8d nails were specified.and judged by inspectors. Diameter, or shear is that factor that makes them strong enough or suitable. Therefore, the reference to diameter. Sometimes the normal length interfered with other parts of the construction , think steel beam with 2x framing attached, and the short nail were made.