Child Benefit is a payment subject to Habitual Residence Condition. However, Child Benefit is classed as a Family Benefit under EU regulations. Therefore, EU/EEA citizens and Swiss nationals working in Ireland satisfy the habitual residence condition for Child Benefit.
From the guidelines:
Child Benefit is classified under EU law as a Family Benefit. Applicants whose entitlement to Child Benefit derive from the application of the provisions of EEC Regulation 1408/71 do not have to satisfy the condition as European legislation takes precedence over Irish legislation. In effect the EU rules contained in Articles 73 to 76 of Regulation 1408/71 governing the payment of family benefit to migrant workers from EEA Member States override the habitual residence requirements under the Social Welfare Acts.
These rules apply to employed or self employed EEA nationals, who have become subject to Irish PRSI since coming to Ireland, and their entitlement continues if they become unemployed and receive Irish Unemployment Benefit.
But if an EEA national comes to Ireland, and never works, they would be subject to Habitual Residence Condition. Also, if you lose your job, and don't claim benefits it seems you may lose this entitlement.