> The value comes from doing the thing. Fixing the tractor creates value. Growing and harvesting the potatoes creates value.

The value from value doesn't come by default; it's not a given.

Neither of those things create value unless they are actually used.

Fixing a tractor you neither use nor trade does not create value.

Growing potatoes you will never eat does not create value.

So, sure, labour can create value, but it's not a guarantee. Trade, OTOH, always creates value.