When does your website need (or needn't) a responsive design?
First, even if you already have a responsive design and you know how to build a responsive website, you cannot claim that you don't need an app. It is necessary to determine whether an app will enhance your website and attract more new users, or it will become a waste of money. Everything you need is to understand what you can give your end users.
why use responsive web design
Sample of responsive web design
See what website type you should choose. Read Responsive web design vs adaptive web design. How to make your choice?
However, if you just intend to create a website, you should think about whether it is worth developing a responsive web design or make a non-responsive web design for a start. It depends on a goal you want to pursue. Let's find out when you need a mobile app, and check out benefits of responsive web design as well.
When mobile app is the option
A mobile app can better than a responsive website in the following cases:
You plan to provide users with some specific services, and the app can turn this idea into reality in a full way. And your app icon on users' phone will help them remind about your product, so brand visibility is in action.
It can be achieved with the help of offline access, and the app only can give it to users. The website doesn't allow anybody to use it without the Internet connection.
Mobile app is an add-on
Website and app should have different purposes. For example, your website can be a description of your product and offer users advantages your product gives. But to use a specific service, they need to download a mobile app. Mobile version of a website and mobile app is a different thing. There is no sense to create an app that will contain the same information the website has. In this case, it is better to create a responsive web design. Importance of mobile-friendly websites is also very high.
Native functionality is used
Let's take Instagram app as an example. This app has a web version, but its target audience uses a mobile app specifically. Why? Because mobile Instagram app makes use of phone camera, geolocation, and it also provides users with a quick access. Given the above, if your product requires using native functionality of mobile devices like contacts, camera or GPS, then a mobile app is what you really need, and it can bring more profit than creating a responsive web design for one website.
Game or online store
When you already have a website of such type, you can keep on building a responsive website as well, since people can use it from mobile. But to keep all elements of your product active and functional, you need to have a mobile app.