The random password generated produces a nine character string of three lower case letters, three digits, and three more lower case letters. This is a total of 308,915,776,000 possible strings, which would be rather hard to guess.
Password requirements often include a need for upper and lower case letters, numbers, and symbols. While this will increase the number of possibilities in a given password string, it makes it difficult to convey the password to others verbally.
A password of “abc123xyz” is much easier to convey that “2xYm4($2y”. While the latter string is one of 51,998,697,814,228,992 possible nine character strings or 168,326 times more possibilities, in reality the addition randomness offers little security gain while radically reducing the ability to convey the password when necessary.