The point is, I shouldn't need to exert any mental energy at all. Code is read more than it is written. The onus is on the author to make things clear.

The example provided is trivial, sure. As complexity increases and you have more cryptic variable names to juggle, you'll be glad for the explicit, clear names.

Also, keep it mind that code will need to be comprehended in less than ideal circumstances. The engineer getting woken up in the middle of the night to fix a bug in production will not be at their mental peak. They'll be grateful for the clear naming conventions.