In my experience roll for stats could cause problems in PNP/ MP, but in SP it should be the player´s choice so the three options will be valid. Heck, If they want to use all 20s or all 10s in level one using cheat engine it´s their choice. They can play the way they want.
That said, I seem to recall Sven said that "roll for stats" will be in BG3 in an interview or in the Reddit AMA (IIRC, feel free to correct me)