Help! What's the advantage of Blockchain-driven Steemit over e.g. Reddit?

Recently I had a conversation with a friend and I was trying to sell him the advantages of Steemit over classical forums such as Reddit. Of course I mentioned that you can earn money with it and that Steemit is based on the Blockchain.

My plea, however, didn't convince my friend. He replied that Reddit could also introduce a reward system and that therefore, he doesn't see any advantage of Steemit over Reddit.

I tried to argue with the Blockchain, but at that point I realized, that I don't know enough about it and so I decided to put the question in here: what advantage does the use of Blockchain give Steemit over, say, Reddit?

Couldn't we just use a normal database like MySQL? Why Blockchain?

Any help would be really appreciated :)