The instant the device is powered, the uncharged series capacitor might be exposed to the highest instantaneous voltage of the sinewave line voltage and this determines the surge current the capacitor and the diodes used to rectify are exposed to. Depending on the ratings and the value of the series resistor to the capacitor, this series resistor value may need to doubled as well, or you may see smoke one time(maybe not even the first time) this thing is turned on. It all about the winning the line voltage lottery on turn on, where all the winners are all getting zero.
X2/250V would be preferred to win the lottery too. Pillow-shaped caps are quite fashionable, but I prefer square ones 'cause they don't move around so much, even though its harder to find them, well, red. Just dull yellow or green or gray, rarely pink, seems to be the popular choices.