You don't think it's easier to develop in Java than assembly? And setting aside the development experience, it might be easier to hire Java programmers.

I was wondering the same; I guess it would be easier to refactor step by step (renaming functions and variables as you work through the code)

From experience, i have seen cobol code stashing entire copybooks into char/varchars, along with some binary switches to select the appropriate copybook. Unless you have the copybook or a translated version, it's pretty much unreadable. In general it's useful if only to interface with those old parts you don't want or can't change.

According the the article, they want to move from a local environment using assembler to Java, which apparently gives them a direction for network access, including web.