In the last few months, I've been to two F2F tournaments (Boston Massacre and Cascadia Open) after playing exclusively online online since 2014. In both tournaments I placed 5th out of about 20 players, and took home best countries for Austria and Turkey. Now, anyone is able to go look at my WebDip GR and see that online, I am a mediocre player at best. You can look at my win and draw percentages (subtracting 1v1 stats) and see that mediocre would be a generous description of my online game. I am happy with my F2F results and I think they are quite different than my online results. I don't "try harder" F2F, I don't slack off in online games either (see my RR). So, my conclusion is that being good at F2F does not auto-translate to being good online. I think what makes me good at F2F is time management skills, interpersonal social/communication style, and my ability to read non-verbal cues in others. None of that truly matters online and my tactical game is so-so (or more gently put, a work in progress). I believe that online, even in FP games, tactics trump diplomacy. In F2F it's the opposite.
Just my opinion, feel free to GFY if you don't agree.