TL;DR: Nanoleaf app: Bluetooth and Wifi. Smart Home Ecosystems: Wifi only.

Nanoleaf app

The Nanoleaf app uses a proprietary protocol separate from Matter to communicate with Essentials devices. Using this protocol, we are able to support pairing and control via both Bluetooth and Wifi. Even in the unlikely scenario where your Wifi network is unavailable, you’ll still be able to rely on the Nanoleaf app to control your lights within Bluetooth range. The Nanoleaf app will always prioritize Wifi over Bluetooth as long as a Wifi router is online and your light is detected on the Wifi network.

Smart Home Ecosystems

Smart Home ecosystems (Apple Home, Google Home, Amazon Alexa, Samsung SmartThings) all connect with Essentials Outdoor String Lights devices using Matter (surprise!). For Outdoor String Light, Matter uses Bluetooth during the pairing process but only supports control over Wifi. All of these ecosystems also require a 2.4 GHz Wifi network to function with Matter, ensuring that automations/routines can execute reliably as well as providing remote control of your devices when away from home. 

The following are the Matter-compatible smart home hubs (Matter controllers) :

Apple: Apple HomePod mini, Apple HomePod (2nd generation), Apple TV 4K (2nd generation and 3rd generation WiFi + Ethernet 128GB model)

Google: Nest Wifi Pro (Wi-Fi 6E), Nest Hub (2nd gen), Nest Hub Max (learn more)

Amazon: Echo (4th Gen). The following eero devices are Thread border routers but not Matter controllers: eero Pro 6E, eero Pro 6, eero 6+, eero 6, eero PoE 6, eero PoE gateway, eero Pro, and eero Beacon (learn more)

Samsung: Samsung Station, SmartThings 2018 Hub (IM6001-V3P01) and Aeotec Smart Home Hub (learn more)