It is written in the link you wrote, that they decided to create a switch to El GAMAL from MW, and they will push it more if there's QC threat
Maybe this is a recent update that you haven't read
No, you misunderstood. See
https://docs.grin.mw/wiki/miscellaneous/switch-commitments/#introducing-switch-commitmentsThey use Pedersen commitments, but the Pedersen blinding factor itself is tweaked (as in taproot) to allow for revealing an additional El-Gamal type commitment. Which potentially allows for a future migration to a post quantum scheme if ECDLP hardness is threatened by quantum computers.