At the same time, since everyone can use every scroll, the real question could become ,"why would you ever play a wizard?" if your battle-master fighter could cast all the same spells as them just as easily, from scrolls.
Right now, everyone being able to use every scroll, regardless of class, is WAI... and if that's the case, it's not unlikely that wizards being able to scribe everything is intended as well.. however, there's a been a lot of feedback on this and it's likely that one or both of these things will change to move more into line with 5e rules at some point in the development.
