Basically its great because everything is client side so all you have to is make frontend websites for people to interact with, and even that isn't really necessary. You just need people, with wallets, to be able to interact with your smart contract easily.

The smart contract you deploy has to address a pain point for existing users, typically by consolidating multiple transactions they are doing into a single transaction.

Your smart contract can take a cut of the transactions that flow through it.

The ongoing overhead costs are practically non-existent. The initial costs to deploy your smart contracts can vary to be several hundred dollars at time of writing.

It doesn't really matter what people think is happening in the blockchain space, or their infinitely moving goal post to reinforce their view about a lack of use case. The reality is that there is a market and there are market needs, just like any other market. The distinctions in this space is that the payment system is built in and all the users bring their own connection to the nearest servers which store all your variables. It's not different than any other financial services, just way faster and permissionless to get a foothold in.