Is this brush good for acrylics?

Yes. It is designed for acrylics, and the synthetic filaments stand up to water-based paint and frequent rinsing. It also works with oil and Griffin Alkyd colors.

What does size 10 mean here?

Size 10 is a mid-to-large round, about 0.22 inches wide at the ferrule with a 1-inch bristle length. It suits blocking in color and medium strokes rather than fine detail.

Round or flat for a first acrylic brush?

A round like this one is the more versatile first brush because the tapered tip covers lines and broader strokes. Add a flat later for crisp edges and heavy body paint.

Will the bristles splay over time?

The tapered polyester filaments and seamless ferrule are built to keep a controlled width of mark and resist splaying. Rinse and reshape after each session to keep the point.

Can I use it with oil paint?

Yes, Winsor & Newton lists it for oil and Griffin Alkyd colors as well as acrylics. Clean it with the appropriate solvent after oil use.

Is the short handle a problem on a large canvas?

The short handle gives close control for tabletop and smaller work. For large upright canvases, a long-handle brush lets you stand back and reach more easily.