The thing I liked the most is that it had real-time stock management, so it could tell you if something was in stock when you place your order, and guarantee that you get everything you ordered.
Ordering groceries online from the major supermarkets in the UK can be frustrating, because they simultaneously stop you ordering items they think will be out of stock on your delivery date (regardless of whether that's the case), and they have no idea what will be in stock until the day of the delivery.
I think grocery delivery through services like Uber Eats and Deliveroo suffers from the same problem - if your item is out of stock, or the driver can't find it, you won't get it.
In terms of the market, there are probably just too many companies trying to do the same or similar things.