What is Magento?

Magento is a Open Source Ecommerce Platform that is Designed with Ecommerce in Mind, unlike Other Frameworks it is build to support 3rd party development and deployment through modules that can be installed and managed though the magento specific CLI interface that has many features that allow developers to easily manage their app
so far Magento is the best solution out of the box for ECommerce Stores who are small to mid sized businesses, and yes it is not recommended for thous who have a large scale business because it is not made for them, they will require to build it from scratch and there is no way around that.