Gwen competing in the marathon is like Michael Jordan or Tim Tebow trying baseball.
Only, Gwen was SUCCESSFUL, not only hanging with the elite marathoners, but beating a lot of them. And doing this after winning a high level triathlon a week ago is a testament to her superior skills.
She will go back to high level multisport training within a week or two while the "elite" runners will try and figure out how to eat more EPO and not get caught next year.