How useful is carry capacity.

I used to think the Aztec +5 carry was a huge bonus but now I am not so sure. It doesn't make them actually harvest faster all it really does is means they save a bit of time not walking back to the camp which isn't all that much. Wheelbarrel and Handcart work the same way.

Has anybody quantified exactly how much of a bonus carry capacity is and when to research it/how much of a bonus aztecs get from it?

Also I am aware that they both synergize with farming well because iirc it takes the same amount of time to farm regardless of capacity.