If you're doing debouncing in hardware, key thing is to make sure the signal that when the signal passes from the analog domain to digital, that it is via a digital input with hysteresis, usually a
schmitt trigger.
Particularly 1/ for counting and keypad applications, where doubled-up edges will result in erroneous values, and 2/ when used as an interrupt input.
0.1 millifarads seems a bit high (and battery hungry) but, hey: if it works, it works. ?