Your code creates a temporary dictionary with {...}, passes it to the update method, which uses it to iterate through all its items and add them to the dictionary. Then gets rid of the temporary dictionary.
My code adds one item to the dictionary.
No temporary data structures are created or destroyed, no methods are called, no iterations. It just does what it’s supposed to do rather than getting it as the side effect of something more unnecessarily complex.
Unless you cycle through thousands of rows, you will not have any noticeable effect. But as you get familiar with python you will realize that my line is easier to read. You look at it and immediately understand what it does, while looking at yours, you need to think a little to understand what’s going on or why was done that way.