Why generate exactly 15 characters?
An exact-length generator is useful when a system has a fixed rule. The tool creates the requested length directly, so you do not need to cut characters from a generated value.
Randomness instead of patterns
Human-created passwords tend to contain names, dates, keyboard paths, and predictable substitutions. This generator selects each character with the browser’s cryptographic random source.
Password or passphrase?
A random password is a strong choice when a password manager stores it. If you must remember and type the credential, a longer random passphrase may be easier.