Other than cosmetic looks and perhaps the safety aspect that
CAT7RDR mentioned, I doubt that much is being done for the short life the tires will have before the threads are showing or its get to what ever point of wear that you replace them. Perhaps if this is a seldom ridden bike that you take out once a year and the tires can last twenty years or more, perhaps it helps.
As always YMMV, particularly those that have unique conditions for both riding and where they store their bikes.