When and where

Hello!

I’d love to hear your valued opinions..

‘Many evolutionary biologists posit that humans developed language for economic reasons. We needed to trade, and we needed to establish trust in order to trade. Language is very handy when you are trying to conduct business with someone. Two early humans could not only agree to trade three wooden bowls for six bunches of bananas but arrange terms as well. What wood was used for the bowls? Where did you get the bananas? That transaction would have been nearly impossible using only gestures and unintelligible noises, and carrying it out according to terms agreed upon creates a bond of trust.

Language allows us to be specific, and this is where conversation plays a key role.’

Source from : We need to talk, Celeste Headlee

#1. Language allows us to be specific, and this is where conversation plays a key role.

#2. Language allows us to be specific, and this is when conversation plays a key role.

My question is whether it is okay to use "when" instead of where in the orginal text.

It sounds okay to me since where/when can both be used because it’s an interpretation of place/time respectively. If the speaker is thinking about a place (a situation for example) they use where. If they are speaking about an instance, or specific time, when can be used.

In the above paragraph ’WHEN' sounds correct, it uses the ‘instance’ understanding.

If I use 'when' instead of 'where', is it grammatically incorrect?

If 'where' is only possible in that context, what are the reasons?

Thank you in advance.