There's a lot to learn about applications.  Languages, JCL, file locations, build routines and so many other things that it makes it hard to bring new people up to speed.  ISPW softens the learning curve by pre-configuring application life cycles, tools, JCL skeletons, and file names, and by storing and filling in meta data that developers typically have to memorize.  New programmers can be truly productive in days, not months.