There are a couple possible benefits that are pretty important imo. The ability to have an immutable ledger keeps things more honest, but that means the nodes have to be spread over multiple parties that won’t coordinate. That’s where the different parts of the supply chain come in. Each step might want to modify data for its step in the transaction history, but it won’t allow the others to do the same. This adds up to nobody being allowed to edit the history- creating a trusted data source. The ‘miners’ don’t have to be proof of work which is what I believe you’re thinking of. You could have other consensus algorithms that don’t cost as much to operate and avoid the situation of miner arms races altogether.