For now, Xbox says that a "random subset of Alpha users" will be seeing this feature, with more Insiders to follow. Eventually, as long as testing is all a-okay, the feature will eventually roll out to all Xbox users.
"Home - Xbox Wish List
Today, a random subset of Alpha users will notice we've added your wish list directly to Home. Just scroll down from the top of Home to check it out."
This makes a lot of sense to be honest - the latest version of the Xbox dash has plenty of store content within it, so why not show users what they know they already want to pick up? We can see this being handy for keeping track of discounts on wishlisted titles.
Last month, Microsoft added some other big features to the Xbox Insider program, including new streaming options for Discord users and a new installation feature to provide users more flexibility with game downloads.