You are confusing two different ideas here. The Canvas format is MIT licensed in the same way that Markdown uses a BSD-type license. That means we are giving explicit permission for anyone to use the format and build apps, scripts, plugins on top of it.

Photoshop/PSD on the other hand is a closed proprietary format: https://en.wikipedia.org/wiki/Proprietary_file_format

You’re focusing on a single word in a sentence which was just about the format.

Yeah and its developed by Adobe which creates a walled garden around there products making file format interoperability very difficult.

Obsidian on the other hand uses open formats with open standards. The difference is NIGHT and DAY.

And if the goal is taking freedom away from the people who are using your product, or to artificially keep people using your product because you know you are making the world a worst place to live in, making that type of propriety software is not OK, even though there are plenty of misguided organizations and people who do it.