Hue products can technically be used without a hue bridge, but neither smartthings nor hue recommend that as it can mess up your Zigbee network. The official integration requires the hue bridge, and you do get a lot of advantages that way.
See the community FAQ (the topic title is a clickable link)
There’s no reason to be concerned about having multiple Bridge/Hub Devices in your home automation set up, any more than you should be afraid of having multiple circuit breakers on your home’s electrical system. It can spread out the load, add additional features, and provide engineering efficiencies.
If your concern is the interface, that’s a different issue, and smartthings itself is an app that can handle many different brands of devices. You may have to set up different devices with their own app initially, but after that, you can generally treat them as all one system. 