The top energy of the accelerator might not be a good judge of how practical its technology will turn out to be. The maximum center-of-mass energy of CLIC is 3 TeV [1], far in excess of what would currently be considered practical. Nevertheless the technology developed for CLIC is now being looked at for providing very high-energy electron beams for cancer therapy [2]. Making something like the FCC isn't just a matter of making a bigger copy of the LHC, it has its own specific challenges [3,4].