The fundamental mistake here is thinking that languages need to have a ‘point’ or be ‘justified’ in order to exist. All languages exist because they served a purpose at some point: communication. Many languages have lost that purpose throughout history and lost out to other languages, to the point of dying out. In fact, languages die out on an almost daily basis, probably faster than ever before.
It used to be very common (and still is, in some places) for people in power to believe that their own language was inherently superior, while languages spoken by other peoples in the areas they control were ‘barbaric’ and ‘degenerate’ and could only lead to cultural breakdown. The English in particular were advocates of this line of thinking, forcing English on all their colonies throughout the world, including Ireland, where the use of Irish was banned and severely punished for centuries. This is a practice that has dealt death blows to many languages throughout the ages.
These days, the most prevalent view is that languages are precious things to the world in general. In addition to being the primary means of communication for a group of people, they tell us a lot about cultural history and contain a lot of the ‘soul’ of a people. Losing a language means forever losing a window into the psyche and spirit of the people who spoke it and the way they view(ed) the world. You could argue (and some do) that things like cultural history and anthropology are equally without worth or merit, but that is far beyond what this linguistics site is for.
To the people who still speak the language, of course, it is part of their identity, and asking them what the ‘point’ of it is would be bizarre. There are still people in the Gaeltachts who grow up thinking and speaking in Irish from the day they’re born, and ‘getting rid’ of Irish would be no less destructive to those people than getting rid of English would be to you.
To comment directly on the arguments against Irish:
Partly true. The government does do a fair bit to promote the language, though not as much or as drastically as what, say, the Israeli government did to promote (enforce, really) Modern Hebrew. Promotions of Irish mostly work by way of incentives and schemes to give additional benefits to those who choose to learn it. It’s working in the sense that daily Irish speakers tend to be more highly educated than the general population, but it is unfortunately entirely true that daily use of Irish is in decline, especially in the Gaeltachts. This is partly because the Gaeltachts are all rural areas, and people are moving away from due to poor local employment prospects.
Downright false. Irish is not an unusually hard language to learn. Its grammar is very different to English in many ways, but overall no more irregular than English (e.g., only 11 irregular verbs, whereas English has at least around 200), and its spelling system, while complex, is significantly more phonetic and logical than English spelling.
Arguably true (at least in the past), but not really relevant. Irish used to be taught quite terribly in the past (a relict of its ill treatment by the English), but from what I’ve heard from younger pupils and students (and their parents) over the past decade or so, this has changed a lot. It is now generally taught as well as any other subject. The terrible way it used to be taught is probably to a great extent responsible for why so many people in Ireland feel so negatively about the language; the fact that it is now generally taught as a living, breathing language is also gradually helping to change the majority view of the language. The fact that it’s not used much as an everyday language outside the Gaeltachts makes it harder for the language to grow and thrive, but until the day it reaches the tipping point of actually being the first language for a majority of people in such areas, this doesn’t make much of a difference. The Gaeltachts are the lifeline of Irish, and it remains an everyday language there.
True, but irrelevant. Being a minority language does not make a language any less useful. Cantonese is a minority language in China, but still has more than 100 million native speakers and is thriving; Faroese is the official and majority language in the Faroe Islands, but has barely 50,000 speakers (even fewer than Irish) and is much less ‘safe’ than Cantonese from outside influence (from Danish and English, in the case of Faroese). Irish is a relatively small minority language spoken in a country where English is the primary overall language (in terms of actual ability and usage); this is invariably a difficult position for a language these days where English is the world’s lingua franca.
So what is the ‘point’ of Irish? The same as the point of English or any other language: communication and identity-shaping amongst its speakers.
What is the point of Irish to people who neither like nor use it? Probably none. But what is the point of Swahili, Thai, Nahuatl or Mongolian to such people? Probably also none. That doesn’t mean these languages don’t have a point.
In that regard, what is the point of English to the hundreds of millions of people who never speak it or deal with it? Also none.