It's superior for a certain problem domain, one in which the desired feature set is unknown, the desired feature set is simple, and the consequences of failure are limited. Consumer web & mobile startups, basically, as well as some limited small-business B2B software where the alternative is an error-prone manual process. It's probably not appropriate for enterprise software, and is certainly not appropriate for embedded, regulated, or safety-critical software.

This is far from the whole software industry, but it's a segment that tends to be of disproportionate interest to HN readers, given the startup-focused origins of this site.