Even ignoring looks, which some users value, Apple may have good reasons for this choice. Because of environmental concerns modern USB cables are fairly stiff.

Even ignoring looks, which some users value, Apple may have good reasons for this choice. Because of environmental concerns modern USB cables are fairly stiff. What would the usability of this fairly light mouse be with such a cable attached? This design also almost guarantees the battery in this device will not be connected to a charger for long durations. That may be good for keeping the battery healthy.