The app simply takes the ordering functionality that Zomato introduced, and puts it in a different package with the same options - we downloaded the app and saw that the experience of ordering is identical to what Zomato was offering - with the only real change being the colour scheme, which is a cheerful yellow instead of Zomato's usual red.
According to Zomato's blog post, there are three main reasons for the new app being launched. For one thing, the focus on a single function will allow Zomato to improve the user experience and create a clutter free app. The company notes that tracking the order status in the main Zomato app takes a few taps, while it has its own tab in Zomato Order.
Also, since the two apps are separate, it means that Zomato Order does not have to be updated every time the Zomato restaurant finder has a small change, or vice versa. At the same time, Zomato writes that the two apps will be linked to each other, and you will be able to go from looking up a restaurant in the Zomato app, to placing a delivery order in the Order app.
As of now though, this functionality is not present - and in fact, you can still order food through the Zomato app. This option will presumably go away, to be replaced with cross-linking between the apps.
Another interesting thing that came up in Zomato's blog post is that there are more apps coming in the future from Zomato. The company has been promoting Zomato Cashless as a way to pay at restaurants, and has talked about table bookings in the past as well - potential future apps from Zomato.
The reasons that Zomato presents in the blog post certainly seem compelling, but this means keeping yet another app on your phone, and possibly many more over time. At a time when companies are moving away from websites and focusing on apps, it's becoming highly inconvenient for users to keep filling up our phones with one app after another.
From being easily able to carry out multiple functions in a single app, we're now being faced to hop from app to app in a frequently cumbersome process.