According to an Ars Technica report, Motorola would only commit to regular security patches instead of the specific monthly update scheme established by Google. Motorola, which went to great lengths to proclaim how revolutionary the Moto Z line was at Lenovo Tech World, went into further detail with a statement issued first to Ars:
In essence, the Lenovo-owned company will regularly update its latest phones, but they won’t come as rapidly as Nexus devices (to be fair, very few phones do). It’s worth noting the Motorola's recent track record isn’t great, as the 2015 Moto X tends to get security releases about once a quarter. And even the just-released Moto Z is on the May security patch, placing it two months behind.
The impact on you: How a company treats security updates is one of the details you should consider when deciding on your next smartphone purchase. There’s plenty of malware, though with regular updates and good practices you should be fine. It’s easy to check if you have the latest Android security patch, which is issued every month by Google. Being smart should keep you safe, but if those monthly updates are important you may want to look elsewhere.