if you are playing off your tablet or phone the sound quality is determined by that device. you may 'hear' a better sound from your laptop with an external card, but the music you create in BIAB stays in the digital realm all the time up to and including the transfer to mp3. so the mp3s will be of the same quality as the original biab files and only leave the digital realm and enter the world of audio when you play them.

so as long as you are not recording the end result will be as good as your phone or tablet - not limited by the soundcard on the laptop.