I think that might be counterproductive on cockroach - the ideal key has locality for data accessed together, but also has writes generally spread across the key range. If all the new rows have a similar key prefix then the shard covering the end of the key range will be hot which limits scalability.

This is a difference from PG, where having all the writes be concentrated in the key range is helpful as the Btree nodes covering that will be more likely to be highly cached