"Γιατί όχι;"

[S.Eleni]

Just curious, would this be used in the same way as it is in English? That is, not only as a way of saying: "Why is the answer "no"?"
But also as a more convoluted way of saying yes, e.g:
"Shall we go for a walk now?"
"Sure, why not."

[FiliusInCa]

Duolingo... Γιατί Ναί;