That certainly seems like a plausible thing that could be happening, but the specific claim of the article is that this is an issue with Airplay, which to my understanding involves devices that are connected to your router / access point, not free standing devices with their own access points that have to be scanned for.
There might very well be latency issues involved with the WiFi radio scan modes on Macs, for all I know, but I don't think they could be related to this specific issue with AirPlay?
The problem seems to be that they bundle all these features into AirPlay with the intention of making it easy to use. It uses device discovery that is not bound to the current LAN.
"When looking for other devices, an Apple device broadcasts a very small Bluetooth advertisement indicating that it’s looking for peer-to-peer services. When any peer-to-peer-capable device hears this BTLE packet, it creates or joins a peer-to-peer network directly between the devices. The devices concurrently switch between this temporary network and any infrastructure networks they were on before in order to deliver both the AirPlay video stream and provide existing internet service. The temporary network typically operates on Wi-Fi channel 149+1, but depending on the hardware involved, may also include channel 6, or channel 149,80. The devices follow the same frequency use rules on the temporary network as they do with any other Wi-Fi connection to avoid disrupting any existing infrastructure networks that might already be using those channels."
There might very well be latency issues involved with the WiFi radio scan modes on Macs, for all I know, but I don't think they could be related to this specific issue with AirPlay?