Technically, they are VCAs...sort of. They're implemented in such a way that they have (as a rule) two VCAs with an inverter in the control line of one. Each VCA gets an equal input signal feed, and the control signal works so that if one VCA is opening, the other is closing. In that arrangement, though, they're a pain to use for amplitude control. Plus, panners tend to use linear VCAs which, because our hearing reacts to sound pressure as loudness in an exponential manner, don't really work well for controlling the amplitude in audio lines. Exponential VCAs work best for that, although you can use linear VCAs if you're controlling them with an exponentially-weighted control signal, like an exponential envelope.
Plus, consider going with a VCA arrangement upstream from your final mixer that allows you to CV manipulate individual VCO outputs. With that Quad VCO, you could pair up an Intellijel Quad VCA which also functions as a 4-1 mono CV mixer, and with the right VCA control inputs (maybe using Doepfer's A-144 Morph Controller?) and VCO tunings, you can do things like swept additive harmonics over fundamental-type combinations from the other VCOs. Or a lot of other things besides!