These experimental clocks are generally not used for time keeping. They are room-filling atomic physics experiments, which are not reliable enough for permanent

These experimental clocks are generally not used for time keeping. They are room-filling atomic physics experiments, which are not reliable enough for permanent operation. It is better to think of them as frequency standards. This means that the clock laser will have the same frequency in a month as it does today (to a very high level of precision). If you have multiple such frequency standards, you can put them in different locations and compare their frequencies via optical fiber links. The frequencies are affected by gravitational time dilation, so this can be used for mapping the earth's gravitational potential. In the future, it might also allow detecting gravitational waves.