Micropayments is a strong real-world use case. Basically, pay half a cent to each website you visit or for each news article you read. Transaction fees are to

Micropayments is a strong real-world use case. Basically, pay half a cent to each website you visit or for each news article you read. Transaction fees are too high for this to be viable with traditional payment systems, however solutions like lightning network solve for this. Gambling is another big one, trust is a problem with online gambling but with blockchain it is possible to make it provably fair by basing randomization seeds on blockchain data. There are many sites running similar setups, and these sites cause a large number of on-chain txns, arguably already paying for sustained innovation. Smart contracts have a lot of potential but are still in their infancy, and bugs have caused significant financial losses, however, those problems are solvable.