Decentralization and auditing. If you put some code on AWS there are two potential issues.
Firstly you don't know if AWS has actually run your code. They could potentially replace your code with their own modified version which does something malicious (like add a bias). For example in a voting system, code could be modified to ignore X percentage of unfavourable votes, or change unfavourable votes to a more favourable candidate.
Secondly I don't know what your code on AWS does. This isn't great for financial and voting systems that should be audit able.
With Ethereum you can view the code for a contract to validate it does not "cheat". You can also trust the contract was executed correctly because the miners have validated it and added it to the block chain.
well, not specifically ethereum but stuff like siacoin provide cheaper options than AWS and while I personally cannot attest to the performance, they seem to be interesting alternatives.[1]
In the case of siacoin, at face value it seems to be significantly cheaper than AWS or Google Cloud for providing bulk cloud storage.
Even more exciting for me is IPFS and Filecoin. Seems like this pairing could allow for a truly decentralized Internet. Ycombinator had one of the founders / lead programmers on the podcast in the last few weeks and I highly recommend it!
siacoin is relatively slow, it took me ~2 minutes to upload 40mb of stuff. But really it's meant to be cold storage and at $2/mo/TB it isn't that bad. The speeds will also increase with adoption.
