For the markdown editor, at least, I suspect it’s often based on impressions from a couple of years ago, when it was very basic. They’ve improved it a lot since then.
I don’t use RTF anymore, but I agree that the rich text editor hasn’t moved on in the same way.
This is certainly fair and a legitimate concern. I will say, however, that the Exporter app works very well with Apple Notes. It exports both the note and attachments and thus far has been flawless. 
I’m sure you know this but for the benefit of those in this forum who may not, while you can’t select specific notes, you can select specific folders, which may export more than I need but in this case, that is a friction point that I’m happy to live with.
Don’t say this, more ammo to switch to Apple Notes 
Well, to add to your temptation, 
I just learned how to uncheck an entire list of checked todo items in AN, see here. Thanks @Tony!
Also, the ability to easily APPEND a document, picture, etc, to an existing AN is fantastic and fast.
So ……
This is an easy trap to fall into with Obsidian, but it is possible to keep your formatting compatible with other Markdown editors.
For the most part, is a phrase with four words. None of my plugins have their own custom formatting, because I’m trying to keep things compatible. However, if I use something like Dataview (for example), its syntax lives on a dedicated page, I wouldn’t mix it in with other notes.
That said, I don’t think it would be a big deal. If you moved to something else you might have a few lines of junk to clear out of your notes, but words are still words and Obsidian’s Markdown flavor is loosely based on the CommonMark spec. If you had task lists or kanbans, you’d have to recreate them anyway when you leave Obsidian.
I was afraid of this too when I switched, so I made a list of alternatives. Obsidian uses [[wikilinks]], which are supported by pretty much anything that uses Markdown and claims to link pages together, it’s the autocomplete while typing that I was worried about losing. Zettlr, Logseq, iA Writer, etc. have support for this, and there’s Foam and Dendron for VS Code. Also, wiki software, where it originated.
It also won’t export link attachments (like when you use the share menu from Safari). I’m glad I hadn’t deleted the old notes yet when I discovered this issue a couple weeks later.
Do you know if this is the same format used by DEVONthink?
Yes, DT3 can use [[links]].
It has three settings for wikilinks: MashedWords, [[square brackets]] and Names and Aliases, and you can choose any or all of them.
It also has tools to deal with the links: you can verify them, you can update the links if the source note’s name changes, and you can convert them to x-devonthink links.
One of the quick ways to create links from within a document is to have the ‘automatic’ option on, then type the name of the note you want to create in brackets: [[New Note]].
When you click inside the bracket, this creates a new note with the template you see in the screenshot, complete with links back to the source note and any other details you want. It’s a very nice quick way to create with meaningful boiler plate.
