How much does neatly eating matter? What about other food manners?

I just read this post about the importance of sandwhich eating skill. The author describes how his investment firm served very hard to eat food to potential clients.

During my internship, a Prestigious Private Equity Firm was looking to improve its stock price/shareholder base. So a delegation of higher-ups (the COO/CFO/Head of IR/Head of Legal) went around pitching their stock to institutions that they thought might be interested in buying and holding it for a long time. These sorts of meetings were a fairly common occurrence at my old firm—we’d have perhaps an average of three or four a week—and would sometimes be catered.

The meeting with PPEF was catered. The meal seemed like an almost-intentional[ii]selection of food items that are difficult to consume in a professional setting—sandwiches with way too much mayo, kettle-cooked potato chips (the extra crunchy kind), and chocolate chip cookies that crumbled if you bit them. There were napkins, but there were not enough napkins.

The people from my firm almost uniformly avoided the food. A few nibbled carefully on the cookies; only one—a portfolio manager with a fierce intellect and a lack of regard for what others might think of his presentation—dared eat a sandwich. Much like any normal human would[iii], he went through several napkins and looked rather undignified at times. (Though this was unimportant, because he was the one who would decide if PPEF would get the investment it wanted.) I of course ate nothing, because I was an intern focused on taking good notes and not appearing overly intimidated.

All four PPEF delegates ate every food item we provided—to do otherwise might have been rude. What’s more, they did it with a shocking amount of grace. Chips seemed not to crunch; any filling that threatened to escape a sandwich was carefully corralled. Napkins were almost unnecessary and were fastidiously refolded if used. In their manners and mannerisms, the PPEF delegates were precise and uniform. None of this appeared to take any attention. It all looked as natural as breathing. In fact, though food was surely being eaten, it almost seemed that they were not eating at all. When they later typed on their iPads—while making frequent eye contact with everyone across the table—their fingers did not so much as smudge the glass.

The author correctly points out that the executives must have been selected for sandwhich eating skill. Obviously it is bad to leave food on your face/teeth or have bad breath. I don’t do those things but I tend to eat in a pretty messy way. How much is that going to hurt me if I stay in software? What if I move to other fields?

[Question] How much does neatly eating matter? What about other food manners?