Yes, building dApps like games, NFT marketplaces, or DEXs on Sui can be profitable, especially since the ecosystem is still growing and offers lower competition compared to more saturated chains like Ethereum or Solana. Sui is designed for scalability and low transaction fees, which means you can deploy and run apps without spending a lot on gas or infrastructure. The cost to deploy a basic smart contract on Sui is usually just a few cents because of its efficient execution and storage model. However, if you're developing something complex like a DEX or a full-featured game, the real cost will come from development time and team resources—not transaction fees.

What makes Sui especially attractive is its support for features like zkLogin (easy onboarding), instant finality (fast UX), and parallel transaction processing (better scalability), which can help you attract non-crypto users and scale more smoothly. There's also support from the Sui Foundation, and you might be eligible for grants or ecosystem support if your project aligns with their goals.

For more technical and up-to-date info on costs, tools, and ecosystem support, you can visit the official Sui docs at https://docs.sui.io. If you’re serious about building for long-term value, now is a good time to get involved before the platform becomes more crowded.