Identity-aware access improves the quality of access decisions. It does not remove the need to limit which systems can communicate in the first place.
Different controls, different questions
Identity answers who is requesting access. Segmentation limits where the request can travel and what remains reachable after a credential, device or application is compromised.
Assume identity controls can fail
Tokens can be stolen, federation can be misconfigured and privileged groups can be assigned incorrectly. Network restrictions reduce the consequences of those failures.
Separate administration
Management interfaces deserve dedicated paths, stronger authentication and smaller source networks. They should not become reachable merely because a user has access to an application.
Use both deliberately
Identity can provide contextual authorization while network policy constrains exposure. The combination is stronger because neither control is expected to solve every problem.