I have both, and a manual lathe and mill, and a laser cutter. 95% of everything I do is with the 3D printers. There is no indexing, no work holding, no dealing

I have both, and a manual lathe and mill, and a laser cutter. 95% of everything I do is with the 3D printers. There is no indexing, no work holding, no dealing with shavings or smoke or dust or cutting oil that gets everywhere, no accidentally breaking your last end mill, no screwing up the only one of the thing you're cutting into, no cutting down stock so it fits in your machine, etc. You just press print. Setting up another machine is a right hassle by comparison. 3D printing and plastic parts isn't good for everything, but it is good enough (and easier) for a lot of things.