What problem IPVM solves, do we need IPVM for Iroh?

[silicology1]

I am trying to build a decentralized server with iroh for offchain computing.

According to ipvm

Why Content-Addressed Data?

Computations are returned as content identifiers (CIDs), which is verifiable data that can be cached anywhere in the network without being tied to one location. 

Does such features can be build with iroh? Isn't ticket in iroh a CIDs for computation?

PKI examples given with iroh. Can one use UCAN with iroh?

I am not sure what IPVM solves, that one can't do with iroh?