This might make sense if North Korea hasn't mastered onboard inertial guidance yet. Early US ICBMs, the Atlas, and (probably) the Titan, were radio guided from the ground. The Minuteman and Polaris were and are completely self-contained after launch. That took a lot of development, much of it done at MIT's Draper Labs.

Today, you can buy fiber optic gyros on Alibaba. The accuracy might not be good enough for hitting a silo, but it should easily keep a rocket roughly on course. It's surprising that N. Korea doesn't have reliable full onboard guidance by now.