The mobile app industry is huge and the iOS and Android ecosystems are extremely popular. The most popular native programming languages for creating iOS and Android apps are Kotlin, Swift and Java. And when using cross platform React Native and Flutter are rising in popularity among other frameworks. The fact that we have access to so many tools and frameworks makes the bar for entry quite trivial so long as you already know a few programming languages. It is something that anyone can learn. Developing mobile apps is not new and the ecosystems are already quite mature with big named apps such as Instagram, Tik Tok, Twitter among many other established apps. However many companies still require apps for their businesses and there are so many other categories that are ripe for new innovations.
I think one of the biggest reasons for being a mobile app developer is attaining that prestige that comes along with it. Having your own app in one of the major app stores gives you a strong brand awareness as pretty much everyone owns a mobile phone. So if you could get even a few of those people to install your app then you can feel a sense of accomplishment. Like the saying goes Rome was not built in a day so if you can manage to get just a few metaphorical bricks set then you have the groundwork set. The first app that you make does not need to set the world alight. But if you keep at it then eventually some will make a mark. This is a great way to have a passive income too depending on the apps that you make of course.
Building mobile apps has got to be one of the best ways to build your brand as well as a portfolio. Having your app in an app store gives you a commercial platform to reach your audience. And having a product that you can show to people on your mobile phone not only makes you look like a professional. But it also adds to your credibility as a developer.