Indeed, out-of-the-box support for custom features/functions in new devices + always getting the latest firmware updates from the official source are usually the main benefits of using the manufacturer’s commercial Zigbee gateway/bridge/hub with their own branded devices.
The main downside to that (other than having to maintain different brand hubs in multiple apps) is that manufacturer’s own Zigbee gateways/bridges/hubs normally only support their own brand of devices, and Zigbee heavily relies on mesh networking using indirect routing over Zigbee Router devices in the Zigbee network to achieve better range and coverage, so optimally you want to keep all your Zigbee devices on the same Zigbee network if possible to get good range and coverage.
Zigbee radios have very short range and poor wall penetrating signals to its network mesh technology and Zigbee Router devices is the key to a stable Zigbee network, and that will not work well in practice if you need to use a different Zigbee gateway/bridge/hub for each brand of devices that you buy if you only have a few devices connected to each and spread out those far away. See these tips which apply to all Zigbee solutions (even proprietary Zigbee gateways/bridges/hubs ) → Guide for Zigbee interference avoidance and network range/coverage optimization
