Both have vendor lock-in though. A WordPress site is portable, it runs on anything with PHP and MySQL. SQspace and Webflow only run on their own servers.
Webflow has zero lock-in. It spits out static sites with standard semantic HTML/CSS and you can take the code anywhere. They also have an API, so you can export collections.
Squarespace, yes, you're locked in.
Re: the portability of Wordpress, I'm not sure how many Wordpress site migrations you've done...but I wouldn't use the word "portable" to describe the process.
Webflow HTML on its own is useless because it is not dynamic. You still have to set up code snippets inside the markup so it can display the menu, or post and page information stored in the database or flat files of whatever CMS you're using.
Webflow CMS solves that problem, but with vendor lock-in.
