I'd argue these reasons are not as good for hardtails. Better chainline, wider range, tighter steps, shorter cage, ability to dump gears with one click and integrated chainguide - these are all good reasons for 3x or 2x system. As far as I can tell there's only one valid argument against them, the better retention of the narrow wide chain and the kinematics of the rear suspension, 0k two. One could argue that clutch derailleurs are enough for retention? At least somewhat? So one or two good reasons.
The clutter on the handlebars, the weight and the brainfreeze associated with the operating the front derailleur are laughable imo. I thought the fd would sneak back to xc hardtails via the gravel but apparently not.
Back to my 90s cave.