What google.ie actually rewards
Irish SERPs visibly favour Irish relevance: .ie domains (with their verified-connection registration requirement that users broadly trust), Irish-market content, euro pricing, and the corroborating details, Eircodes, CRO registration, Irish contact routes, that tell both Google and buyers this business genuinely serves Ireland. UK sites drifting into Irish SERPs serve those users badly (sterling prices, GB-only delivery, UK phone numbers), which is precisely the opening a properly Irish presence exploits.
Vocabulary and reference points
The differences run deeper than spelling: institutional references (Revenue not HMRC, HSE not NHS, solicitors' structures, planning terminology), seasonal and cultural anchors, and the simple credibility of examples drawn from Cork rather than Croydon. Irish readers notice; conversion follows the noticing.