WYSIWYG - the ability to click anywhere and just write, is so nice.
Drag and drop images from elsewhere into one’s notes. Again, so nice.
I keep switching back and forth between Tiddlywiki and Notion. Notion isn’t perfect, it is slow and the search function sucks, but I find myself switching back to it again, mainly for the above two reasons. I hope one day Tiddlywiki can include the above features.