So if Chat Gpt 4.o is free for all , what is offering paid subscription?

As per title of the question , what is setting chat gpt paid subscription apart from the other new addition and free for all 4.o ?

Free users can only access GPT-4o when (if) there’s spare capacity. I haven’t been able to access it yet.

The How can I access GPT-4, GPT-4 Turbo and GPT-4o article has some explanation.