What is the point of the ''@localhost user in MySQL? [closed]

Question

Quoting MySQL docs:

If you cannot figure out why you get Access denied, remove from the user table all entries that have Host values containing wildcards (entries that contain '%' or '_' characters). A very common error is to insert a new entry with Host='%' and User='some_user', thinking that this enables you to specify localhost to connect from the same machine. The reason that this does not work is that the default privileges include an entry with Host='localhost' and User=''. Because that entry has a Host value 'localhost' that is more specific than '%', it is used in preference to the new entry when connecting from localhost! The correct procedure is to insert a second entry with Host='localhost' and User='some_user', or to delete the entry with Host='localhost' and User=''.

What I can't understand is why is this entry there in the first place? I fail to come up with any purpose they could serve.

Could I have potentially broken something by deleting them? (One of the suggested actions in the quote above)

Note: I know there are multiple questions asking why user@'%' won't work and answers containing this exact quote. What I want to know is why is this problem(?) created in the first place.

Answer 1

It is an anonymous account and can be used for various purposes where you don't want to have to specify a username and password, such as within a script.

Granted this is a security hole but is also limited to being on the localhost. You could also alter the grant privileges of this anonymous account so that it can only do selects on a particular database or even single table.