There are probably several ways this question can be answered.
But the main reason for Analog Devices to provide the ADuCM360 IDE, was to give customers a low cost, open source option to do their development and prototyping. All the tools and plugins are based off of GNU open source tools, and customized for the ADuCM360. This makes it free for all users to download and recreate in their own systems, to do the designs they want to do.
With Keil and IAR, there are free trial versions of the tools, but in order to be most useful, customers need to pay for the full versions of the tools. With the ADuCM360 IDE, there are no limitations including code size, and there is never anything to register or pay for.
