Re: Obsidian vs TiddlyWiki, for me, I think Obsidian wins because they have a mobile app. While for TW, we have to use a mobile browser.
Also, it appears easier to do the simple stuff, like linking and transcluding (section transcluding too!). TW is basically good ol' method of typing.
However, as a wiki or blog, at least for me, TiddlyWiki still wins, and easier to publish.
In a corporate environment, since I like making documentation especially when there are none, I'll choose TiddlyWiki. But if I want collaboration with at least 5 people or so, I think Obsidian is the best option. (And the mobile option makes it easy on-the-go.)