Whether it has benefits is up to you, but from a technical perspective they’re as expensive as VLANs, so basically free. It’s the same receive and transmit radio, the only difference is that it broadcasts and responds to two network names at the same time. The maximum power consumption is the same: the max the radio will pull when at full load. The minimum power consumption has to be ever so slightly more since it needs to broadcast two network IDs, but those are measured in bytes and sent a couple times a second, it’s negligible compared to the cost of just running the radio.