Resistors come in Standard Values with different tolerances. This allows for a degree of overlapping of values without having to manufacture a vast range of values.
But if you require a more precise value of resistance, say for a Timing Circuit, then a better Tolerance Value (1%) would be preferred.
Although Resistors are a cheap passive component, when buying 1000’s at a time, cost might be more of an issue.Therfore if your circuit will function well enough then a a not so good Tolerance Value (5 or 10%) would tend to be a cheaper option.
Also Resistors come in many shapes and sizes depending on how much Current it will allow to travel throgh it, or Voltage across it. This will govern what wattage the Resistor needs to be too, and there are several “Triangle” calculators such as Ohm’s Law to help with this. The higher the wattage, then the size tends to increase. The Makerbuino 4k7 or 4.7k or 4,700 ohm resistors are probably 1/4w or one quarter watt. 1/2w resistors would be physically a bit big, plus would cost fractionally more.