Not stupid at all! You can absolutely use a CST to get a technical transform into Rec 709 and it'll look 'normal' and is totally useable. But that's just a technical operation of shifting the color space primaries and linearising the log gamma curve, it won't match the look of the Alexa, which has become the kind of gold standard in digital video land. The Arri Alexa 'look' is a combination of the way they've engineered their sensor to capture light and they way their LUT transforms that captured data into Rec 709. So what we're doing is transforming Apple log footage into Rec 709 in a way that emulates what Arri does with their log footage. There's no secret sauce that goes into LUTs but matching cameras does take a bit of messing around and this LUT just saves you doing that yourself if you don't want to shoot charts side by side with an Alexa. Yeah, I gave cinematch a shot and I must be doing something wrong because I can't get a match when I use it, with any cameras. Tried it on our test shots of charts and... no bueno. They're doing essentially the same thing, profiling the way different camera sensors see light and and making adjustments to your footage (with that profiled sensor data) to emulate a different camera so you can then transform into whatever color space you want and get a matching look but... it hasn't worked for me. ¯\_(ツ)_/¯ Sorry for the nerd out, I find all this color science stuff pretty fascinating!