You could use the same thing to argue that business logic shouldn't be in PHP, or that it is hard to version control, because my predecessor put all of his func

You could use the same thing to argue that business logic shouldn't be in PHP, or that it is hard to version control, because my predecessor put all of his functions in one giant PHP file and frequently updated websites live on the server without committing those changes to SVN. Anything can be mis-used. Whether or not we should use it should depend less on potential for mis-use, and whether it can be used correctly (and in a multi-developer environment, whether or not you can enforce correct usage in some way, either through technical or social means).