Life is all about compromises. Gliders and our racing planes use high aspect ratios for the same reasons. Te reduce induced drag and tip vortex loses. They just do it at different G loads but the reasons are the same.

Aerobatic models suffer from the higher loses of low aspect ratios but suffer it willingly to gain in the far smaller momets of inertia that comes from keeping the center of masses of the panels in closer to the center of mass of the model so that it can accelerate in roll faster in order to accomplish the flight goals.

By the standards of aerodynamic efficiency the aerobatic designs are terrible ugle lumps that do not deserve to exist in a perfect universe. But they do very well at what they can do. And that's the point.