Apple has changed the Safari browser to limit the life of cookies to one week to increase privacy. Great, but many things rely on cookies, for example, affiliate sales. If someone buys something after 7 days you will not be credited with the sale because the cookie will have been deleted. Your income would be reduced.
I wonder if this will affect other things, like logins to websites, pop-up notices that you have either declined or accepted – next week you may get them all over again. Site options and preferences may be discarded after a week. I can see a lot of potential disadvantages, but I don’t know how this will work.
Few people use Safari for web browsing globally, but usage among Apple owners is quite high. If your audience is mainly US Apple owners, you could be affected.