The point of what you heard is likely that gold is thought by some to hold its value well, when the money market would provide negative interest rates. These negative interest rates are a sign of deflation, where cash money is worth more in the future than it is today.
Normally, under inflation, cash money is worth less in the future than it is today. Under 'normal' circumstances where inflation exists, interest paid by the bank on money held there generally keeps up with inflation + a little bit extra. Now, we are seeing many banks offering interest rates in the negatives, which is an acknowledgement of the fact that money will be worth more in the future than it is today.
So in that sense, holding physical gold 'fights' deflation [or, negative interest rates], in the same way that holding physical cash does [because if you hold onto a $10k bundle of bills, in 10 years you can walk into a bank and it will be worth $10k in future dollars - which in a deflationary market would be more than it is worth today]. Some view gold as being better at doing this than just holding cash, but that discussion gets into an analysis of the value of paper money as a currency, which is outside the scope of this answer.
Suffice to say, I do not personally like the idea of buying gold as an investment, but some do, and partly for this reason.