The most striking feature of a mini amplifier is excellent sound quality at low volume. While you can use an amp of any wattage during your practice sessions, if you ask any guitar expert, they’ll recommend mini amps will lower wattage.
The reason for this is that lower-watt mini amps sound much better at lower volumes. Yes, that’s true. You can buy an expensive 100-watt amp, and even use it for your practice sessions, but what’s the use? It will distort the sound quality at low volume, and you’ll have to struggle for sound clarity.