I was under the impression long range missiles aren't much use in global warfare anymore, because they are easy targets for missile defence systems.

Even if your target doesn't have missile defence systems, any ally of theirs along the route can intercept too.

Multiple sources think that the real range is an ICBM level. And the Indian government purposely limits it's range. No strategic reason to communicate a larger range than needed and why have an headline that reads, "India develops capability to nuke Europe or US"?