Well it depends. For example, calculators have been around for a while and a calculator that only performs better than the average human is not very useful. Sorting algorithms are another example.
Autocomplete/intellisense in an IDE is probably the most salient example. An autocomplete that performs _as well_ as the average programmer is, well, totally useless.
I'm not sure what you mean. Autocomplete usually just gives a big list of options for the next word, so even getting the most relevant ones to the top would be helpful in less-memorized codebases, and actually filling out entire lines as well as an average programmer is not useless at all.
Oh I agree about filling out entire lines. I use copilot to write boilerplate based on a template pattern I provide all the time.
It’s not very precise though. Autocomplete will give me a list of valid APIs for current given version of any library sorted by most recently used with a locality bonus. Copilot on the other hand does not have that level of precision. Two different tools that I use for slightly different things.