Very good question.
Simple answer - No, you won't be able to login as another by chance. You understood it wrong. If 1000 users try to login as you, the results of our statistics show that one of them may be able to do it.
But if you combine typing biometrics with other authentication factors, using it as a two factor authentication (2FA) or as a multi factor authentication (MFA) solution, this scenario won't exist at all.
So yes, typing biometrics is a very strong and efficient authentication method.