Why isn’t Topical Dutasteride the “Gold Standard”?

Based on my research, Dutasteride is far more effective than Finasteride at preventing hair loss. Due to its molecular weight, Dutasteride is not absorbed well at all and remains within the skin. If topical Dutasteride is more potent than Finasteride, and doesn’t have the systemic affects, why don’t more people begin with this treatment? For context I started Oral Finasteride January 1st and am considering switching to Oral Dutasteride. Is there something I’m missing?