Some of the ways a security team can use MITRE ATT&CK include:
Conduct a security gap analysis and plan security improvements
Strengthen cyber threat intelligence
Accelerate Alert Triaging and Investigation
Create more realistic scenarios for red team exercises and adversary emulations
Assess maturity of security maturity of their SOC
Communicate clearly and concisely to stakeholders
Acquire a common language which is helpful when working with consultants and vendors