There is absolutely no reason why you couldn’t resell an EC2 standard RIs yourself on the marketplace. However, the true value of Archera Guaranteed RIs is that we are contractually obligated to purchase any GRIs you sell back to us, immediately.
The challenge you will encounter with attempting to sell RIs yourself is that there is often very shallow liquidity available. Meaning, you can list the RIs but there is no guarantee that they will sell in a timely manner, or at all! With Archera’s GRIs, you have the peace of mind to know that your RIs will be immediately purchased.
Additionally Amazon is constantly updating their policies around what RIs are able to be resold on the Marketplace, which Archera's Rebate GRIs are not subject to. So even in the case your organization cannot use the RI Marketplace, Archera can still provide a flexible, short term commitment option.
Finally for any commitments that aren't EC2 standard RIs such as RDS RIs, Sagemaker Savings Plans etc. there is no public marketplace you can take advantage of so Archera provides the only way to resell or receive a rebate in the case of any underutilization of those commitments.