The chief limitation? Right now, there aren’t many pickup locations. You’ll have to live in Atlanta, Berkeley, College Park, Columbus or Los Angeles to take advantage of the service, and it’ll only make sense if you’re close enough to swing by on short notice. However, these pickup points tend to be on campuses, making them ideal for students — you can snag a phone charger in between classes.
About the only question is whether or not Instant Pickup will expand much further. It’s highly dependent on Amazon having fully-staffed retail presences chock full of basic goods, and there’s no guarantee those will spread far when Amazon’s attention is currently focused on grocery shopping. For now, at least, this is more of an upgrade to Amazon’s existing pickup strategy than a fundamental shift in how it does business.