AgentCooper do check this out quickly, as I think if you register yourself before your child is born on the register mentioned on this thread, then your child will be an Irish citizen.
What's the benefit- well, even if your husband/partner doesn't have the same citizenship, it gives you and your child (and them usually) the right to go and work and travel not just in Ireland but the whole of the EU bloc, plus things like uni may be open to your child for free (which is a way off admittedly). I can't see why you wouldn't do it in uncertain times, there's no downside at present as there's no duel taxation and there's advantages to having an EU passport holder in the family, if in the future you can't hold both, you could choose.
My children don't hold an Irish passport but another EU one, I am truly grateful for this as the only way we have benefited out of the Brexit mess where we felt unpopular and awful for being a mixed immigrant family- Farage obviously feels the same which is why he's got German passports for his children, I guess (if that's what he was doing at the embassy).