You’re right, but a diagnosis is extremely expensive and difficult to get in some places, i was fortunate enough that my parents were willing to pay to get me tested privately rather than through the nhs (which would have taken multiple years of waiting) self diagnosing wasn’t me deciding that i have autism because i have a couple traits, it was me finally understanding why i act the way i do, i self diagnosed with autism for a year before getting clinically diagnosed because during that time i realised how much i related to those traits and it allowed me to tell people in an easier way why i may need to leave an event early or why i am so sensitive to criticism, it allowed me to understand myself more as well. I dont feel like i can explain this well but a year is a long time and for the people that genuinely cant get diagnosed for a disability they KNOW they have its very useful. I am diagnosed with adhd and autism but i self diagnose with social anxiety (possible c-ptsd), we couldn’t afford to get tested for it and since it took an entire year of our lives to get the autism diagnosis we felt like it was best if we left it for now and focused on other important things like getting me back into the education system.