If learning disabilities are separate from autism, then surely mental health issues, like anxiety, are also separate? I've taught lots of young people with anxiety, it can be crippling, but most of the young people aren't autistic. They both co-occur, but they aren't the same thing.
Autism is such a vast spectrum and I do think removing some of the 'functioning' language, and other diagnosis like Aspergers, can be problematic.
Take my DS, and my friend's DS as examples, neither have learning disabilities and both have the diagnosis of Autism Spectrum Disorder:
My DS: Gets up in the morning and makes himself breakfast. Gets himself dressed and ready for the day. May need to be reminded that an item in on the wrong way round, but he has got much better with this lately. Goes to school, very academically able so does not need any support with his lessons in that regard. He is very bouncy so sometimes needs to be reminded to sit still. Needed social support in the younger years, but has now settled into a small friendship group. He is also happy to be on his own if his friends want to do something he isn't interested in. Comes home from school. Helps himself to snacks and drinks whilst I am working. Usually plays on Roblox, watches the TV or draws. If there is no screen he can be hyperactive and bouncy, needs to be reminded to calm down as he might hurt himself (don't jump off the furniture!) May have a chat about social skills / appropriateness depending on what has happened that day. Eats dinner, whatever I've cooked. Gets himself showered, dried, pyjamas on and does teeth. Goes to bed and reads.
My friend's DS: Non-verbal, they have tried may ways of communication (signing, pecs), so far they have been unsuccessful. Incontinent so still in pull-ups, though my friend is trying again to train him after lots of regressions, so he is having multiple accidents a day. Needs assistance with all personal care needs. Very sensory sensitive, really struggles to be around groups of people, loud noises, bright lights. Needs 24/7 supervision as he cannot be left alone, is a danger to himself and others because he can be unpredictable and lash out. Interested in flicking light switches on and off, watching the washing machine, spinning. Very repetitive behaviours. Tries to escape from the family home and school all the time. Has to have a very strict and regular routine or struggles to cope. Has a 1-1 at school, not interested in other children, gaining very little from lessons and academically behind; can't read, write, count. Friend is now having to consider a special school. Does not sleep at night and when he does sleep, wakes several times.
To just say both have 'Autism Spectrum Disorder' doesn't tell you anything. In this case, the traditional understanding of Aspergers and Autism actually works much better.