this may sound stupid but it has been bothering me for quite a while, i did a 3d animation course but it wasnt video game oriented so i don't really know, from what i've learned modelling in triangles isn't very animation friendly because they don't bend well and they create distortion and to only model in quads, but recently i've been looking at 3d models optimized for video games and i noticed that they were pretty much all made of triangles, for example this one



so i'm wondering, in video game industry do you have to model only in triangles, if so why?