How to say "What's the point?" in ancient Chinese

What’s the benefit? The meaning of "what's the benefit?" can basically be used interchangeably with "what's the point?"

What’s the point of talking too much? Only when he speaks. ——"What's the point of talking too much"

What's the point of leaving under impeachment? ——"Shao Yong Trying His Best"

Or you can use "in vain" instead. I think the translation between ancient Chinese and modern Chinese will be fine as long as the meaning is clear. There is no need to use the speaking habits of modern Chinese to copy the ancient Chinese < /p>