Not necessarily. An Ergo Dial or rear dial is simply a brand's own proprietary adjustment system rather than the licensed BOA system. Functionally, they work the same way: you turn a dial at the back of the helmet to tighten or loosen an internal harness around your head.
The real difference is that quality can vary depending on how well a particular brand implements their system. Some feel just as smooth and secure as BOA, while others may feel slightly less refined or durable over time. That said, most mid-range to premium helmets using these systems still deliver easy one-handed adjustment and even pressure distribution.
If you're choosing between the two, focus on how the specific helmet feels when you dial it in. A well-made proprietary system is still far better than a helmet with no dial adjustment at all.