Both mobile apps and mobile websites have their own importance and role for different businesses. It totally depends upon the type of business and its objectives. For example, if you want to interact with the customer, build customer loyalty, brand presence, and want your customers to access your brand offline, then, mobile apps are the best. They act as a brand entity and are built for specific platforms, like iOS or Android.
However, if you want to present mobile-friendly content to a wide range of audiences, then a mobile website is the best option since they are responsive websites and can adjust different screen sizes.