Differences between Power Apps and traditional app development approaches
Compared to traditional app development, Power Apps projects are different in two key areas:
How various members of the organization work together to create the solution
Differences in who develops the app
Power Apps is a platform that benefits both "pro developers" and "citizen developers."
In a traditional development environment, only pro developers could be involved with the actual making of an app. With Power Apps, everyone has the power to build the apps they need by using advanced functionality that was previously available only to professional developers. Power Apps "democratizes" the custom business app building experience by enabling users to build feature-rich, custom business apps without writing code.
Differences in development methodology
With traditional app development such as the "waterfall" model, where the process flows downward from the design phase through release, there's a long lead time before a user actually sees the working app. As a result, there's an increased risk that there will be gaps between what the user initially requested as a requirement and what the app developer created.
Even with more modern development approaches such as agile development, a significant amount time can pass before the first minimum viable product (MVP) is delivered to users.
With Power Apps, you can quickly create a usable version of your app, because Power Apps provides a WYSIWYG (what you see is what you get) development experience. Users experience the actual working app very early in the development process, and if new requirements arise, new features can be added to the next version.