As Satoshi Nakamoto put it:
Transactions that are computationally impractical to reverse would protect sellers from fraud, and routine escrow mechanisms could easily be implemented to protect buyers.
Bitcoin in particular, and probably most other cryptocurrencies, are primarily concerned with moving money from actor A to actor B without needing to trust actor C. They generally do not address how to guarantee, without a trusted intermediary of some sort, that subsequently goods will subsequently move from B's control to A's control.
In the Bitcoin world, blockchain mining fees apply on a per-byte basis, so adding a digital "Game of Thrones complete 4K video series" to the blockchain would not be feasible. It isn't a delivery mechanism itself. Maybe you could add to the blockchain just a one-off symmetric decryption key for the video encrypted using the purchaser's public key. Perhaps there's a script for that? Even so, A presumably has to trust that B's website will actually serve the expected digital goods or that the pre-downloaded digital-goods can be decrypted using the provided key.
There's an interesting whitepaper on escrow as a solution with a good set of references
We consider the problem of buying physical goods with cryp- tocurrencies. There is an inherent circular dependency: should be the buyer trust the seller and pay before receiving the goods or should the seller trust the buyer and ship the goods before receiving payment? This dilemma is addressed in practice using a third party escrow service. How- ever, we show that naive escrow protocols introduce both privacy and security issues. We formalize the escrow problem and present a suite of schemes with improved security and privacy properties. Our schemes are compatible with Bitcoin and similar blockchain-based cryptocurrencies.
The first reference is to Atomic Cross-chain trading which begins to address the exchange of digital assets.