That is correct, Hubitat's Hue Bridge integration will not bring in the Hue plug, only lights. The alternative is directly pairing it to Hubitat, though as you note, there is no native HomeKit integration in that case.
I wrote a custom Hue Bridge integration that does support the smart plug if you are interested:
(I'm not sure Hubitat's has really been touched much since they introduced it, so I wouldn't count on anything any time soon there...)
