Shopify Hydrogen is a new way to build online stores using React, while traditional Shopify themes use Liquid templates. With Hydrogen, developers can create faster, more unique, custom shopping experiences. It’s great for brands that want full control and advanced features. However, it requires coding skills and is best for teams with technical knowledge. On the other hand, traditional themes are easier to set up, don’t need much coding, and work well for smaller businesses or quick launches.