I'm not sure, moonman — it's not specified anywhere in the [broken link removed] or [broken link removed], they just say that it's "tailored for our more discerning customers"... (but reserve the right to cancel it if "you are no longer, in our opinion, able to manage your financial affairs").
I wouldn't particularly consider myself in the "high income" bracket, but I did have a good credit history and am in permanent PS employment, which may have helped.
AIB (rather like BoI with the old American Express Blue card, now withdrawn) tend not to advertise or promote this very actively, presumably as it's less profitable for them than their other cards. At least, that was the reason why BoI killed off the Amex Blue — which was a substantially better deal than this, offering 1% cashback. This gives you only 0.5%, and the first €5,000 in each 12-month period doesn't qualify.
But if you're going to spend, say, €2,000/month on your credit card — pretty easily done if you have a family to feed and a car on the road — you might as well get a tenner a month back from AIB for doing it. Spend €50K a year on it and the maximum cashback awardable would be €225. I've submitted claims for smaller tax refunds...