LLMs + Harnesses are incredibly effective, as evidenced by the literal millions of people who are paying quite a lot to use them, who speak glowingly of them and would 'never go back'.

Whatever 'shape they take' - they are obviously useful - ergo - 'you're doing something wrong' if you can't make use of them for most tasks.

Mileage varies, there are downsides, but it's the same with anything.