In practice, this means that you can have all the features you need with none of the bloat, powered by a Linux kernel that's more recent than most other distributions.
Instead of trying to create a single, static firmware, OpenWrt provides a fully writable filesystem with package management. This frees you from the restrictions of the application selection and configuration provided by the vendor and allows you to use packages to customize an embedded device to suit any application. For developers, OpenWrt provides a framework to build an application without having to create a complete firmware image and distribution around it. For users, this means the freedom of full customization, allowing the use of an embedded device in ways the vendor never envisioned.
OpenWrt has long been established as the best firmware solution in its class. It far exceeds other embedded solutions in performance, stability, extensibility, robustness, and design. It is the clear-cut goal of the OpenWrt developers to continue to expand development and ensure that OpenWrt is the foremost framework for innovative and ingenuitive solutions.
To really understand OpenWrt, you need to read About OpenWrt Buildroot!
OpenWrt is not intended to be a ready-made distribution you can directly load onto an embedded device. Instead, the framework allows you to create a firmware tailored to your own particular needs.
Although there are several UI projects available to cover common use cases, OpenWrt is not end user firmware. More advanced tasks require command line operations and basic knowledge about operating a Linux-based system.
Because by employing OpenWrt you can achieve exactly that. The article user.advanced may help you to get started with that.
Because the open architecture enables you to use stateful packet inspection, intrusion detection, and any number of other things that normally require several thousand dollars worth of hardware to do effectively.
At the moment there are more than 2000 software packages in the official repository, and many more provided by the community. The number of packages is evidence of the effectiveness of the OpenWrt build system, which provides the opportunity to easily port packages and create your own firmware.