If you are already familiar with the idea of SEO then ASO would make sense to you. So basically what ASO allows to do is simply
make your app visible and discoverable in the stores (e.g. App Store, Google Play etc.). The logic behind the SEO is the same as for ASO - using keywords to bring you to the top of the search so users can find you faster. So
why App Store Optimization is important? Today, more than
5 million apps are available to download from the App Store & the Google Play Store and its number is increasing rapidly. This means that your app is definitely facing some tough competition.
In case
you want to know key differences between ASO & SEO, here they are in one pretty clear format (
source)