Ethereum enthusiast here, I am no economist nor a huge expert on smart contracts so I would like to see the reactions to what I am about to write.

Is there any example of a centralized application also interacting with a smart contract?
Is this a good idea to begin with?

I am playing with an idea, where I have, let's say an e-commerce website, for every interaction users have with it, buying/selling stuff the application would interact with a smart contract and reward the user with ERC20 tokens. Users can then decide to use those tokens on my application to get discounts or other benefits, or keep the tokens and maybe trade them on some exchange. Maybe even share tokens with other users of my website or other websites using the same tokens.

When users use tokens to get benefits from my website, some of the tokens would be burned to keep some kind of balance in the circulating supply, while some others would be used as fees. This whole thing would have a semi constant supply, by that I mean that depending on the monthly users on my website the smart contract would adjust how many tokens are delivered for every interaction and how many are burned when used. All of these rules would be of course public as part of the smart contract.

Besides the technical issues of what the mint/burn policy should be for these tokens in order to keep the whole thing balanced, I do see some more fundamental issues with this idea, most obvious one being (seems to me) that it defeats a huge portion of what dapps are about, having a centralized server, and having that server being the only one allowed to interact with the smart contract upon user interactions, only direct user interaction would be checking their balance and maybe send the tokens to somebody else. On the other hand I can imagine all of these interactions coming from my server would be publicly visible to everyone and so it would be impossible for me to cheat.

My question is: are there any examples of this in existence or is this just a silly idea?

Thank you