Yes an No. GDP makes sense to start from some baseline year and then sho changes in real dollars to give an idea of economic growth rates and trends.
That graph, however is misleading, IMHO, because it magnifies the apparent growth, making it look like the user base tripped based on relative sizes of the baseline to the peak. In reality, while they have see a significant % increase in users, the overall increase is tiny compared to the overall installed base of browsers in th EU. I suspect such a graph would have Brave be lumped in with "Others." That's not a knock on Brave but a knock on how the manipulates the chart to look more impressive.