Significance of the development & launch of a Synthetic Aperture Radar [SAR]-based satellite, one that India has developed itself, can't be stated enough - India entered an all new realm of Space-based surveillance.
The latest issue of the 'Current Science' magazine has a series of writings covering different aspects of India's first SAR satellite, RISAT-1. A bounty of information, to keep the interested occupied through the weekend, reading it.
Having achieved this, ISRO would now be looking to launch future SAR satellites operating in frequencies higher than the present C-band-based RISAT-1 & work towards generating images at better resolutions. The RISAT-2, procured from Israel, for example, operates in the higher X-Band region & has a resolution of ~10 centimetres. The RISAT-1, on the other hand, generates imageries, at best, at 100 cm resolution in the High-Resolution Spotlight [HRS] mode, a mode that would limit the area it can observe at a time. Thus, while this satellite would provide better indigenous monitoring capability compared to what it had up until then, it doesn't quite cut ice as a satellite used for military-grade monitoring - it is a highly advanced civilian satellite. What it does show, however, is that India is on route to acquiring indigenous capability that would eventually find great use with the Armed Forces.