So, I guess it's really mostly for 3 reasons.
1st. as a lube
String fibers that aren't lubed tend to "cut" into each other and fray out to the "fuzz"
2. as a "sheath"
Helps keep the dirt out of in between the strands where the dirt can/would cause the most abrasive harm...
3. makes sense that some lube will help the fibers even themselves out in tension.
OK..That all sounds good.
In that case, I would think the best thing to do is use a slick lube on the string to lube it internally.
Then rub on/in a good "sheath' of wax on the outside to keep the whole string free of debris.
Thanks to those who helped!