¿UsePass overrides Render State?

I'm trying to usepass the sprites-default shader, but it keeps ignoring the SubShader's Render State... For example, this should draw a black square, but it draws normally

     Shader "Creado/Sprite Enmascarado" {
         Properties {
             [PerRendererData] _MainTex("Sprite Texture", 2D) = "white" {}
             _Color("Tint", Color) = (1,1,1,1)
             [MaterialToggle] PixelSnap("Pixel snap", Float) = 0
             _Mascara("Mascara", Int) = 0
         }
     
             SubShader
             {
                 Tags
             { "Queue" = "Transparent" "IgnoreProjector" = "True" "RenderType" = "Transparent" "PreviewType" = "Plane" "CanUseSpriteAtlas" = "True" }
     
                 Cull Off
                 Lighting Off
                 ZWrite Off
                 Blend Zero Zero
     
                 UsePass "Sprites/Default/"
             }
     }
 

I checked the code from the built in shader, and it seems that the Blend is set outside the Pass block... so, I really I'm wondering if this could work at all ¿Am I doing somthing wrong? ¿Is this a bug, or I'm just stupid and didn't get how "UsePass" works?