it's probably because they scan your codebase/directory for context reading files, searching for references, building understanding of your project. The UI versions skip that.
it does, but i’ve found it to be buggy, got hung up when that directory was not assigned (poor ux), and just crash often. i’ve found the cli much more performant.
The real pain in email HTML isn't writing it — it's maintaining it. Markdown at least gives you something a human can edit 6 months later without crying.