It is just my opinion (and nothing else) that the blockchain should be exclusively used for money.
That's like buying a computer solely for the purpose of checking your email.
Which most people do.
Really? I think most people don't do this. A more apt analogy would be buying a smartphone just to call people. People use phones and computers for a wide range of things and if you just wanted to check email a phone or tablet would be better. I think the fact that the blockchain can be used for a multitude of things just ads to bitcoins value as a technology.
Well the Bitcoin blockchain is and will be used primarily for money. You could have other chains dedicated for other purposes. The only problem I see is that people need an incentive to "mine" that chain. With Bitcoin you get the block reward and transaction fees, but having a useful new Blockchain may not prove to be incentive enough for people to mine it.