Advantage is user has no control/is not needed to consent about what apps they're authorizing to share their information between each other, bacause the decision to delegate access is at the IdP policy level. User many never know which apps/services were authorized to share their information. Wait, is that an advantage? ;-)
For organizations it's definitely an advandtage, as it also allows for preventing data flowing to personal accounts. Right now, any employee could knowingly or unknowingly exfiltrate data, by just connecting to e.g. the personal instead of the organization's JIRA account, and there is essentially no standard way to guard against that as an organization.
That's also blind spot in normal OAuth and I was surprised to find that this was never addressed in all the years that non-MCP OAuth found adoption.
For your employee account yes its an advantage, and thats the target. Your personal account will still require consents.
As someone who has been creating agentic workarounds at my large employer and in a lot of conversations with security as a result, this does not seem to be a huge advantage from the company side. They are very much invested in users being aware of what they permit. The company does want the final say either with shutting down a compromised user or blocking one service from agents and allowing the other, but they 100% do still want employees to be actively engaged and applying their own consent.
Removing that from the employee also removes the employee from responsibility for any breach of information IMO, and companies definitely don't want that lol. What they do want is users to stop complaining about the annoying reauth every 8-12 hours for a dozen services which this does.
The kinds of wishlists I hear are more about users managing fine-grain service permissions for various agentic roles and managing which agents have access to which role, which leans the other direction. They want to allow users are to treat agents like cloud services and have a greater responsibility for applying least privilege, justify leak risks, etc. The onus to protect this data will always be an employee responsibility in the end.
I am with you on the challenges with fine grain authorization needs, to me that part is real hard. In a theoretical world the IDP would know all the roles and permissions available for the different authorization servers (downstream services). However centralizing something like this would require some adoption of how permissions are managed by different resource servers, that is a different battle.
What this gives your employer is the allow list of AI agents that you can use (the ones that can use your employer's IDP to access downstream MCP servers) and filters out all the MCP servers that do not implement this protocol. Essentially the threshold to use any AI agent or any MCP server would be a lot higher.