General question about performance

[Lybrial]

Hi!

In many AddOns I see people doing stuff like that:

local _G = _G;
local wipe = table.wipe;
local remove = table.remove;
....

Whats the big advantage of that? Is it affecting the performance? The memory usage?
Is it for better readability? Just generally: Whats the reason for that?

This would all just create references, right?