The text under the simulation distance selector in the new UI describes each simulation distance in terms of an "N x N block radius" (e.g. "64 x 64 block radius" for simulation distance 4). This wording is nonsense: a radius a one-dimensional measurement; "N x N" describes an area, not a radius.

Moreover, an N x N area is much smaller than an N-radius area:
64 x 64 = 4906
3.14159 * 64 ^ 2 = 12,868

Finally, assuming the intended meaning is "a N block radius", the full text is not strictly correct. "Loads and applies changes within a N block radius" is not how the game works and does not make explicit the connection to the simulation distance being chosen.

A more accurate description would be "loads and applies changes in chunks that come within a (simulation_distance x 16) block radius." However, if the mention of "chunks" and multiplying by the number of blocks in a chunk seems too technical, it could be phrased obliquely as "loads and applies changes based on a N block radius."