I guess it depends on what you do on the Day One app. The only real indicator of whether something is a bujo or not, is if you use the rapid log/bullet point system to organize your day and maybe a monthly log; everything else is nice to have but is not necessary.
I use a simple yearly, monthly, and daily logs, and some habit trackers but I also use a second journal to write down my feelings and pretty much anything I want to say that day; I used to keep them in the same notebook, but now I keep them in two for privacy reasons.
Personally, I don't think it matters what you call your journal practice, as long as it helps you.
I have both a digital system, and a physical one.
For the digital one I was using Tiddlywiki, but now I'm experimenting with Obsidian, which is easier for beginners, but I miss some aspects of Tiddlywiki.