Jack of all trades master of none for me. I'd have one if I had dozens of bikes, but not in place of a road bike
Conversely I have mine because I don't have room for a dozen bikes
And mine is because I don't care about the road bike mastering the fast race end of the road spectrum, but CX allows me to go on the seriously extensive array of bike paths which tend to be packed gravel. And the XC MTB is more than overkill for that.
I don't go out with a road/trail mindset. It's all fair game. CX bike for longer rides on or off road or both or road and have the option to cut off down any old trail whenever I feel like it. XC bike for techier rides that are largely off road, steeper, etc.
Tempted to get 2nd set of wheels (same rim type, so don't need to worry about adjusting brakes), with 25 or 28c road tyres, though for a bit more road oriented distance rides. If I get bored of the traffic, it'll only cost me 2 new tyres to go back to CX only with a spare set of wheels.