Hi Ajit,
Great question. Let me try to explain with a simple example.
If you have a dashboard screen in traditional web that shows data from several places, probably you’ll have some aggregates on preparation. Each of those aggregates will only run after the previous has finished, and the page will only start showing at the end of preparation, after the server has rendered the screen.
in reactive the page is rendered right away, in the browser, and, as aggregates and data actions are being fetched (in parallel), the page gets updated. This can give a much better experience.
Although taking advantage of the speed that asynchronous calls can give can be a technically complex task, OutSystems tries to make this as straightforward as possible.
This being said, this is not the only advantage of reactive, another big one is that screen actions are created in JavaScript and, as such, can run much faster, in the browser.
You can read more about it here: https://www.outsystems.com/blog/posts/all-you-need-to-know-about-reactive-web/
Hope this has answered your question, but if it hasn’t? Please let me know.
Cheers,
Tiago Simões