You’re right. It’s not a lot for a machine. The point isn’t the speed capability. It’s why? What UI has 1,000 rows in, e.g., a table all at once (much less 1M)?
Many plots contain thousands of data points. Eg: 10 x 100 heatmap which supports sorting by various metadata. This is a common visualization for biological data where your data matrix is samples x proteins, so potentially much larger than 1000 data points.