1. If you have SQL keyword, space or any other illegal characters then you need to use square brackets.
2. SQL server parse and compiler much more easy to validate and compile code.
3. code search tools easy to find table names or column names only.

Square brackets are meant to let you treat an object name which would normally not be allowed, as a valid object name. Things like special characters, spaces, and reserved keywords are some good examples.

select [Column with spaces], [1NumberAtTheStart]
from dbo.[User]

If not for square brackets here, none of the quoted objects above would pass as valid object names. The first column has spaces, the second starts with a number, and User is a reserved keyword.

The reason SQLPrompt suggests not using them is that it can make your code look "noisy".

Of course, some times you need them. Say you have a table called dbo.User . If you try to say select * from dbo.User you will get an error. So you MUST quote the object name to keep SQL from freaking out (i.e. select * from dbo.[user] ). It's completely allowable in SQL to quote all your object names if you really want, but it's really meant for if you have object names with spaces, or other characters you need to ignore.