The combination of a time and guaranteed error bound can be used as a primitive in distributed systems. You can get timestamps from requests coming from different systems and relate them in a meaningful way. At least, in a false negative fashion. E.g., if A occurs at T + 100ms with 1ms uncertainty and B occurs at T + 105ms with 2ms uncertainty you can conclude that A happened before B. This does not allow you to always establish an order (e.g., if there is overlap) but this isn't always necessary. For instance if instead you are B and you want to have something occur after some time A with uncertainty A_uncertainty, then you can sleep until B with uncertainty B_uncertainty such that B - B_uncertainty > A + A_uncertainty.