There's no doubt that, whether the desktop ripper or the mobile ripper can satisfy your basic need to rip music from Spotify. However, compared with a desktop, which has more memory space, the ripped songs saved on your phone may take up your limited phone memory space. And mobile rippers may be banned easily or lack maintenance, so they may fail to rip some songs from time to time. Therefore, using a desktop tool, like TuneFab Spotify Music Converter, to rip music from Spotify seems better than using mobile ones.