It does not certify NIS2 compliance. No external scan can.
Of the ten measures in Art. 21(2), none is fully verifiable from outside. The checks touch eight of them — all except risk analysis and incident handling — but touching a measure is not covering it: from outside you see one end of each. What the tool does is produce technical evidence that either contradicts or supports declared compliance.
The asymmetry that makes it useful: a FAIL is solid evidence of a gap, and a check that could not observe the target — a WAF refusing requests, a DNS that will not answer — returns ERROR, never FAIL; a PASS only proves an endpoint was configured correctly at scan time, and the report states next to every PASS exactly what it does not prove. That is why the external assessment comes with an organisational questionnaire covering the measures invisible from outside — risk analysis, incident handling, continuity, supply chain, training, access control, MFA, encryption at rest. Without it, a clean report would imply compliance.