Saying Obsidian uses just TXT files suggest, that I could use any editor and that Obsidians file format is compatible with any editor. That is technically the truth, but the problem is, that if I decide to use another editor I might get problems because of the lacking ability to usefully edit the metadata. So, if I use Obsidian, the files are de facto not compatible with other editors.

Of course I could switch off of Obsidian and I have the raw data, so I am not locked in. But I think stating that obsidan uses just txt files without any explanation is a bit misleading.

But a lot of meta-data is stored somewhere extra.