>>'If I have to open a browser to read your "plain text"....'
If you are able to open a browser to read both plain text (source code) and a rendered page with some text, you can be pretty sure that the person who wrote the code knows what he or she is doing with both.
What happens when your resume is processed/displayed by something that knows nothing about html?
If I have to open a browser to read your "plain text"....