There are tons of projects popping up utilizing blockchain technology, but it always seems unnecessary. With the introduction of a blockchain into the technology stack, you then have to think about consensus algorithms, miners, the incentive for miners, the economics, etc...
That seems like a huge overhead, but maybe it's my misunderstanding. When do I want to use a blockchain? and why should I use it? and how do I approach all those aspects to successfully start a blockchain?
There are many examples where a blockchain can be useful. A value which has once added to a blockchain can not be deleted or altered afterwards, so with a sufficiently strong (i.e. distributed) blockchain you have an ultimate proof that certain data existed at a certain point in time and that you are the owner of this data.
Think for example of a patent database: By the time you file the patent, you create hash values of the relevant documents and add it to the blockchain. If anyone else claims the invention at a later point in time you can proof that these documents have existed when you added them to the blockchain and have not been altered since then by simply calculating the hash value again and checking it against the old value.
Without a blockchain, you always have to rely on a centralized authority, e.g. a national patent office or a central bank.
