The TPM 2.0 requirement for Windows 11 was to offload compute tasks from the cloud. Make end-users process their own analytics, particularly with the AI-based workloads based on private models and which would be expensive to do in the cloud.
The NPU requirement will give capability and TPM requirement will provide obfuscation of workload contents from analysis. End users won't be able to analyze exactly what or how their own machine is processing their data on Microsoft's behalf.