OLAP/MOLAP/ROLAP are interesting technologies to BI folks. Companies say they want to do more BI/analytics, and DBAs/BI managers see an opportunity to get experience with some cool tech, so they say that's the correct path. Now they've got it, even if some indexes and query tuning on a regular DB would have been fine, and want someone who can support it.

And if you think OLAP is unnecessary, you should see how many devs brought in Hadoop unnecessarily.