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You want your regex to match passwords that have two consecutive digits somewhere in the string.
If the \w* is omitted then the regex requires that the two consecutive digits immediately follow the non-digit at the start of the string. By putting the \w*, your regex allows for zero or more characters in between the non-digit at the start of the string and the two consecutive digits.
This answer may also be useful to you: Regular Expressions: Positive and Negative Lookahead Questions