“What need is there to …” vs “Is there a need to …”

Question

Is a question that starts with "What need is there to" grammatically correct?

For example:

What need is there to tell a lie just to make a joke?

If so, is there a difference in meaning or nuance between that clause and "Is there a need to"?

What need is there to tell a lie just to make a joke?

Is there a need to tell a lie just to make a joke?

Answer 1

What need is there to tell a lie just to make a joke?

I would choose this question if I want the responder to respond with the very detail of the answer. This is not a suitable choice if you do not need to know why somebody is telling a lie just to make a joke.

Is there a need to tell a lie just to make a joke?

This is, in my honestest opinion, a “boolean” question: It can not be answered with detail unless the responder chooses to.

Edit: I would like to add that these may be rhetorical as well, as pointed out by others. Alternative rhetorical statements are:

• Why are you telling a lie just to make a joke?
• You shouldn't have told a lie just to make a joke.

These can be used to emphasize that the second person is very, very wrong.

Answer 2

Is there a need?: answer yes or no.

What need is there?: an elaborate answer is expected or the question is rhetorical

to make the first sentence in your example rhetorical, I would expect a really

Is there really a need to tell a lie here?

but the example sentences do not roll off my tongue in any case... They do not sound natural

I would say

Was it really necessary to lie just for the fun of it?