It might be small, but it's one of the key reasons which sets it totally apart. I.e. hardware manufacturers produce GPU drivers for Android, and that's it. Since it's not compatible - it's useless for regular ("conventional") Linux and prevents ports from using this hardware, until drivers appear (may be never). I.e. in practice it causes distraction for HW manufactures, and excuse not to produce X (or Wayland) drivers, since they are already too busy with Android.