Let's look at the data, the chart says "buys/deposits" - does that means deposit + buy, or a regular trades with the equivalent of $1,200 also count? Because if it's the latter, it shouldn't count. Next, the chart is a percentage, and without the absolute values we can't tell how many people exactly bought Bitcoin. So, if we assume that on average 5000 people deposit and buy Bitcoin on Coinbase every day, then the amount of people who supposedly bought Bitcoin with stimulus money is ((0.37 - 0.1) * 5000)/100 = 13.5 people. And looking and this chart, the whole thing lasted only 1 day, so in conclusion very few people bought Bitcoin with their $1,200.