Not every business needs a mobile app, and building one for the wrong reasons is expensive vanity. But for the right business, an app is not a nicety; it is the difference between a customer who comes back weekly and one who forgets you existed. The question is which kind of business you are.
An app makes sense when customers interact with you repeatedly and the app makes each interaction easier: booking a service, paying, ordering the usual, tracking a membership, collecting loyalty rewards. Businesses built on repeat visits, salons, clubs, restaurants, service providers, benefit because the app lives on the customer's home screen and pulls them back. Frequency of use is the test.
If customers interact with you rarely, once a year, once ever, an app is usually the wrong tool; they will not download it, and a good mobile website serves them better. An app that duplicates a website with no added convenience is a cost with no payoff. The honest advice is sometimes not to build one.
When it fits, an app delivers what a website cannot: a permanent place on the customer's phone, a direct channel through push notifications, and a smoother experience for the things they do often. It shifts the relationship from hoping they return to reminding them to. For businesses whose economics depend on repeat visits, that shift is the whole point.
Build it for frequency, or do not build it.
This is general educational information about building software, not specific technical or business advice.