I've wondered about it as well, but right now is not a good time to buy a refurb from Canon. With the lens rebates on a new 85 f/1.2L II, the price is 1859 with free shipping. The Canon store is 1759.2 and they charge shipping and tax. For less than $100, you have 9 months of additional warranty and potentially higher resale value.
The situation was different when they were running sales in the Canon refurb store, but then they were frequently sold out....
Some I know PREFER refurb, because the lenses get inspected more closely.
Whether you buy that or not is up to you, but do have to say I have heard a lot more issues with new products over refurb products.
Your mileage and experience may vary