Strength very rarely matters in knife blades, unless you use knives as pry bars (strength determines the force required to either break the blade or cause a permanent plastic deformation of the blade, i.e. to permanently bend the blade).

What matters is the compromise between hardness (good for edge retention) and toughness (required to avoid chipping).

Many alloyed steels (especially with chromium and vanadium) allow a better compromise than simple carbon steels, i.e. either a higher toughness at equal hardness or a higher hardness at equal toughness.

When you do not specify simultaneously hardness and toughness, simple carbon steels may seem good enough, because they can be made to be either very hard or very tough.

If you cut only very soft things, like fish meat without bones, a very hard carbon steel blade (like a traditional Japanese yanagiba) will not have any disadvantage versus an alloyed steel blade. When you want a more versatile knife, an alloyed steel blade will be superior.