Yes, you can enjoy the hot springs at Ginzan Onsen even if you don't stay overnight. You can choose the public bathhouse, Shirogane-yu, which has a reasonable fee. Additionally, there are free Warakuyu footbaths located at the entrance of the hot spring street. Some onsen ryokans, such as Takimikan, also offer day-use bathing services for a fee of about ¥1,000 to ¥2,000.