A 72-year-old woman with a history of chronic sun exposure presents with a 3-cm irregular, tan-to-brown macule with ill-defined borders on her left cheek. She reports the lesion has been slowly enlarging over 5 years. Dermoscopy shows asymmetry, multiple colors, and an irregular network pattern. Biopsy reveals atypical melanocytes confined to the basal layer of the epidermis with minimal dermal invasion. What is the most significant prognostic advantage of this melanoma subtype compared to nodular melanoma?