Team Nope here ! We teach our children not to lie, create and fabricate stories, be honest, and be truthful and then we turn around and share stories to them about a overweight old man who only works one day a year and has a reindeer with a red glowy nose. Seems so hypocritical.
I don't know how harmful it can be though, because over here Santa in the mall is Samoan one year, Hawaiian the next, then European, then British. Worked it out it was all fake when I was about seven because of this.