It's the only standard that works if you take rights seriously. And, if you take rights seriously, then you place real rights above legal rights.
Any other standard places your right at the whim of others, be it some stronger individuals, a government, or simply a majority in any collective. Tying rights to something you have control over (you have control over making your land efficient) gives you a claim against the interference of others.
By taxing your land, the government ensures that your ownership goes to benefit others and the government provides for your security against the encroachment of others.
What you don't have any right to is to merely sit on resources for your own enjoyment. Not even the "father of capitalism" was willing to grant such a prospect, nor was the largest intellectual influence on the founders ready to grant such a prospect.
Surely you would think that an individual who owned all the land on earth and opted to leave it idle, while everyone else scrambled, is morally repugnant, even if such an individual purchased all that land. One cannot claim on any principle that such and individual is doing something wrong, yet an individual who merely did that with 99% of the land was not.
By taking small steps, we can carry that 99% to 98%...1%.