Metaphor: ReFantazio has a mix of real-time and turn-based combat because director Katsura Hashino wanted it to have battles reminiscent of movies and manga.
Hashino explained the reason for Metaphor: ReFantazio's hybrid combat system in a new interview on the Official Xbox Podcast (timestamped here). In it, he said there are "remnants" of Shin Megami Tensei 3's 'press turn' battle system in Metaphor: ReFantazio, but ultimately the latter's evolved into something that lets you blitz through weaker enemies without expending time and resources on them, and still slow down for big, epic faceoffs with more important enemies.
