Whether you obtain a program of the first type or the second type depends on whether the DFTACTGRP parameter of CRTBNDRPG is set to *YES or *NO respectively.
Creating a program of the first type produces a program that behaves like an OPM program in the areas of open scoping, override scoping, and RCLRSC. This high degree of compatibility is due in part to its running in the same activation group as OPM programs, namely, in the default activation group.
Creating a program of the second type produces a program with ILE characteristics such as static binding. You can specify at program-creation time the activation group the program is to run in, and any modules for static binding. In addition, you can call procedures from your source.