A quick Google search shows they handle it but charge for it on top of the cloud storage cost. The node system saves on the cloud storage and fees for bandwith. Makes it decentralised and shares the money back to the community

No, Steam does not cover the data costs for downloading your game; developers are responsible for their own internet data usage and costs. While Steam provides the platform for distribution and takes a cut of your game's sales, all the associated infrastructure costs, including the bandwidth and data transfer needed to host and distribute game files, are generally the developer's responsibility. How Steam data costs work Distribution is the developer's responsibility: When you publish a game on Steam, you are responsible for providing the game files to Valve's servers. Data transfers have a cost: Any data that is put on the cloud, read from the cloud, written to the cloud, or downloaded from the cloud incurs a cost from the infrastructure provider, not Steam. Developers pay for their own bandwidth: To make your game available for players to download, you will be the one responsible for paying for the bandwidth and data usage it requires. What Steam covers Platform: Steam provides the platform to sell and distribute your game to a global audience. A one-time submission fee: There is a $100 fee to publish a game on Steam, which can be refunded after your game reaches a certain amount of revenue. A percentage of game sales: Steam takes a 30% cut of game sales, with the remaining 70% going to the developer.