This Journal app is intriguing, but I also ask, "Why"? Why is Apple making this app? What's their interest?
I'm a little wary of Apple going into apps like this for a number of reason. Many years ago (I think more than 15 years ago), the two major post-photo editing tools for Macs were either Adobe Lightroom or Apple Aperture. I spend several hundred dollars and went with Aperture because I thought having a tool that is well-integrated into Apple's ecosystem would be a plus. Well, it was a plus for a while until some years later Apple stopped developing Aperture then eventually gave it up. That was several hundred dollars down the drain, but worse is migrating things over to Apple iPhotos which then became Apple Photos.
After that experience, I didn't fully trust Apple to make apps in which usually you would think third-parties would be the one to do them instead.
So why is Apple venturing into journaling apps?