If a country fails to perform the obligations incumbent upon it under a judgment, the only remaining recourse is to turn to the Security Council, which can vote on a resolution, per the UN Charter. This happened in a case brought by Nicaragua against the United States in 1984, demanding reparations for the US support for Contra rebels.
The ICJ ruled in Nicaragua’s favour, but the US refused to accept the finding. Nicaragua then took the matter to the Security Council, where a relevant resolution was vetoed by the United States.
So nothing then? The article is weird to frame them as important and impactful, then its gets undermined by that bit you hi-lighted.
It does matter for anything not involving the USA, Russia or China. If they ever admit that they’re not above the law it would be increibly valueable.