The checked(*) parameters are not applied to the preview display. They are only applied for exporting a VRM file.
VRM version is compatible with 1.0. You can also apply the MToon shader in VRM 0.x, but the display results are slightly different for some parameters, and parameters that only exist in 0.x cannot be set. The "VRM 1.0 only" parameters or mappings will not be reflected when exporting VRM 0.x.
In the 3D view, outlines are drawn using a simple method, so some shapes may not be drawn accurately and may look different from what they look like in an external VRM viewer.
VRM 1.0 uses the sRGB color space, so even if you set the same color, VRM 1.0 will appear brighter or whitish overall than VRM 0.x. [Convert to VRM 1.0] takes into account the differences in color space and allows you to convert so that the appearance does not change.