As the name implies, the hub acts as a central place for all the bulbs to meet up. Using a hub also takes the strain off your Wi-Fi network, but handles all of those bulbs and talks to them directly via a language such as Zigbee or Z-Wave. Hubs have both good and bad sides: On one hand, the hub is an extra piece of hardware to set up and manage. On the other, a hub is often more reliable than Wi-Fi or Bluetooth alone.
Matter is a newer standard that's set to improve interoperability between smart home brands and it's starting to gain traction. Brands like TP-Link, Naoleaf, and many more are already building matter-enabled tech and several mesh Wi-Fi systems, like Nest WiFi Pro, support matter.