Rv are not built to any critical standards. I do not trust the manufactures enough to ensure there are no low spots, trapped water or sagging in the lines. Blowing the lines may work for many but it is not a foolproof solution.
I am not willing to be the guinea pig and find out I had a low spot that held water and was not blown out.
Even if someone with the exact same model successfully used the blow out method, I would not assume blowing lines would work for me simply because RV's are not built to any real standards and there is very little quality control industry wide.
The only real advantage of blowing out the lines is that you can save the $10.00 cost of the anti freeze otherwise there is no real advantage in my book. Adding anti freeze is a simple process.
The water system should still be sanitized in the Spring either way. Unless of course you blow out all the germs when you blow out the lines?