GPT4 (and even 3.5) can do all sorts of magic that makes even the latest Bard look like a joke.
You can use GPT4 to compress inputs down to 1/2 the original number of tokens while retaining 100% of the original meaning. (When the GPT4 generated output is pasted back into GPT4 it's, seemingly, the same as posting the original text).
Defining DSLs in GPT3.5 and 4 is easy, and IMHO better than relying on JSON output (especially before the function calling stuff was introduced).
You can give GPT3.5 and 4 a DSL and it'll suggest improvements to the grammar.
You can tell GPT4 it is an experienced LLM prompt engineer and then ask it to write prompts for GPT4 which you feed into GPT4.
You can tell GPT4 it is an experienced python engineer and that it needs to write a program to parse the output of another prompt which you then paste in.
One time after several hours of fruitless debugging, I pasted a source file into GPT4, told it "there is a concurrency bug here, can you find it for me" and out popped the exact line I had screwed things up on. (Hilariously I had explained how to avoid exactly that same bug a couple years prior to some junior engineers... oops)
I'd pay $100 a month for access to a more powerful programmer centric version of GPT4.
For that matter if OpenAI made an announcement that next week they were gating code generation behind a $100 a month fee, I'd probably just be forced to pay up.
GPT4 is absurdly powerful and I am well aware I'm not even making the best use of it compared to what I see others doing.