why there is no column length in laravel default migrations

hi , i was wondering if it's necessary for performance to set the length for some string columns in the migration , i know it is but how big of difference does it make ?

i mean lets say email column in the users table , i think 50 char length is more than enough ... but there is no length in laravel default users migration so it would use the max 255 chars for string columns

i wonder is it becuz it's not really that important and doesn't make any noticeable difference or becuz it's something that laravel cant predict and they expect coders to set the length based on their need