Low wattage amps have high impedance. So you want high impedance speakers to match.

More wattage = lower impedance = expensive equipment.

The better answer is that the closer an amp's output impedance is to the speakers' impedance, the greater the variation in amplified frequency response. Because impedance varies depending on the frequency of the signal.

So an amp with high output impedance doesn't work well with low impedance speakers. But it's barely a problem nowadays for class AB amps; mostly only tube (which have other problems) and class D amps.

the lower resistance there is, the faster current and power naturally flow. You'd need an amp that expects that.