The 'label' way of thinking is very prevalent. The label people can think what they want, and consider their way of thinking right.. however I can only speak for how much a diagnosis has helped my 18 year old DD and therefore me as a parent.
4 years of EBSA, self harm, 3 overdoses and 2 other suicide attempts (plus less seriously but still very hard on everyone - struggling to hold down long term friendships, stimming, very black and white thinking, feeling awful about herself and not knowing why she couldn't cope with things that friends did and can. And why? There didn't seem to be any obvious reason why all of these things were happening. She is intelligent, charismatic and academic by nature.
Getting DD an ASD diagnosis (now 18) 3 years ago was one of the most useful things ever for her.
She wasn't over the moon to hear it at first, however over the last 2 years she has started to accept and understand herself in a way that she never would have otherwise. I also now have a much better understanding of her, why she struggles with certain things and I can support her in a way that is meaningful now whereas before I was at a loss.
The benefit I am seeing now is that now she has decided education isn't for her and she is in the work place, the world of work (and otherwise) is finally starting to understand neurodivergence in people. Some of the jobs we were looking at yesterday said 'if you have a diagnosis that means you are neurodivergent then we will accept your application. And you will go straight through to the next round'
Of course you could argue that in some instances this is a bit of a box ticking exercise - but as a parent who had done nothing but worry and feel like my DD has been at a disadvantage for the last 4 years, I'll take anything that makes it a bit easier for her and people like her.