[throwaheyy]

It's a lot easier to visually scan for _ than for 'this.', quicker to read code that uses _, and it's about 5 times quicker to type.

[bfrydl]

I personally think reasons like this are just pulled out of thin air to justify simple style preferences. For example, `this` is an entire word that the editor draws in a different color, so it seems unlikely that `_` is easier to scan for. Even I'm not claiming to have objective reasons for preferring `this`.