you would not expect that the purchase of luxury goods would correlate with appreciation in various investment markets?

if not then, when Lambo?

I highly doubt they did this correlation properly. It looks like they just correlated two time series. Both series are correlated with time (both go up over time) and not each other. I eyeballed the series and correlated just the directions, when BTC goes up, it is 50/50 whether or not imports went up. I am pretty sure this correlation would be near 0 if you detrended the time series.