It's in line with the existing tax policy, so I think it's hard to disagree with.

If undertaxed, people will see it as a sign that the government is very lax about it. If overtaxed, people will think the government is too strict, etc.

Crypto is in its literal infant stages in Korea, so I can see why the govt would want to do this in the beginning, and the lower or raise the tax rates according to public response.