The bias helps for stuff like hair or leaves where the transparency is fuzzy due to the compression from fake transparency (masked) in the material.
Not sure it would help but in essence it just makes it so that the image compresses or mips less.
If your texture is too high res to the point you see jaggies, maybe your rendering mode is more at fault than the texture itself?
Like TAA of MSAA vs DSAA vs just forward shading?