A lot hinges on this being true, but being deflationary is not unique to gold. It is also true for a lot of other things, including stocks. Yet we think it is good that regular people spend their earnings on stock, and it is generally considered to be one of the things which made American economy uniquely strong. So much so that other countries seek to mimic it.
The argument should cut both ways: A strong stock market which is deflationary should lead to economic stagnation. Why buy a pizza today when you can buy S&P500 and buy two pizzas tomorrow?
Reality seems to disagree here. People buy what they need and want, today, and whether the rest is stored in fiat currency, stocks, or gold seems to matter very little for economic productivity.