~3% performance gains. I didn’t understood part about $this.
If the closure doesn't use $this (an instance of the current class) then it doesn't need to store a reference to it, which also skips the bookkeeping from the garbage collector.
alt Hacker News
If the closure doesn't use $this (an instance of the current class) then it doesn't need to store a reference to it, which also skips the bookkeeping from the garbage collector.