Probaly 1st used for power gating and not for logic, low level logic that does not need speed.
If contact resisitanc eis made low enough these could be put in series to provide better MTBF for the case of stuck switch on.
Low frequency logic will also be applicable for this.
Blog Doing Math in FPGAs Tom Burke 24 comments For a recent project, I explored doing "real" (that is, non-integer) math on a Spartan 3 FPGA. FPGAs, by their nature, do integer math. That is, there's no floating-point ...