I find it immensely useful when dealing with arrays to be able to 
convert a source argument (that may or may not be in an array) into an 
array so I can concatenate it, perform a set-union on it, etc. with a 
destination array.
What is the real reason for this, and if it's being obsoleted, what am I 
supposed to use instead if I need to insure I'm dealing with an array ?

Thanks,
Patrick Bennett