Watercolor Painter's Palette

This is a brand new painter's palette one of my classmates just bought. It's size is approximately 10 cm x 24.5 cm (4 x 9).
It has a nifty tray to hold several brushes (MANY of the palettes out there DO NOT have this feature), a fold out tray as well as the lid for blending, 24 empty wells into which a daub of color may be squeezed and a thumb hole and thumb rest for when the painter is doing "plein air" which is literal french for "full air", but what it means is "outdoors". When watercolor painters paint outdoors they need to pack their equipment compactly to reduce the weight and bulk, so this palette is much smaller than the average in-studio palette which is about 31 cm x 45 cm (12 x 18) or larger.
Our instructor is always teaching us about "blending" our colors. We can obtain practically every color we need from the three primaries RED, YELLOW, and BLUE, and a BROWN. You can see that this student only has the four requested colors; Alizarin Crimson, Lemon Yellow, Burnt Sienna and Ultramarine Blue
If it had been my palette, I would have spaced the primary colors evenly on one side of the palette with 2 empty wells between each color for easier mixing of the secondary and tertiary colors, but that doesn't make her choice wrong. Everybody chooses the method that feels right for themselves.