There are two speeds here, both defined a bit loosely in part 25.
Vb, the speed for maximum gust intensity, is the speed (usually only defined for larger passenger carrying aircraft) above which an aircraft shouldn’t fly in severe turbulence. It is also usually the maximum permitted value for Vra, which is the recommended speed for flight in turbulence (often the two coincide). Both are semi-arbitrary, and picked following a handling assessment that confirms it is high enough to ensure that a gust-induced stall is highly unlikely during such conditions. It also needs to provide adequate margins at either end between low speed stall warning and any high speed handling effects (sometimes called the low and high speed buffet boundaries).
So Vra is the optimal speed to fly at, and
Vb is the fastest - but if they are the same (a single turbulence speed in other words) there should be no ill effect in flying at that speed, although the ride may be more comfortable slower.
G