1) From 20-50% faster wear rate, to double/triple 200-300% extra wear rate.
Depends on pads/rotors/how you brake/where you brake.

I've had my brake pads roasted in just one track day session from 60-80% left, or even brand new (but already run in a bit prior to the track day), on few occasions.
And all those occasions are blank plain faced rotors. Only my Iswara had x drilled and slotted however the NVH + pad wear (from Iswara experience, at least 40-70% extra wear) shaving my expensive EBC green and eventually ended up all the holes cracked (not one hole without crack), I've learned my lesson.
Yes, expensive AMG cars or M sports cars have cross drilled, but do you know how much those rotors cost? Some of those rotors one piece, not one pair, can cost up wards 5 digits, and those are not carbon discs. Carbon disc some of them one piece can buy a Myvi.
Materials very different.

2) crack = NVH and if serious, whole rotor shatter and you lose braking. Still think doesn't affect much? I've seen people just bang wall (or those very lucky) just go straight into gravel in Sepang because no brakes. And some of those, rotors gone to pieces.

3) no, extra noisy extra NVH.
Logic right? You got extra things shaving your brake pads and it is scrubbing on uneven surfaces and even holes? Logic bro, use that.

So no, 100% untrue.

Cars and bikes not same, no need compare.

OT. A bit: only rich can change all/proper kits one shot.
Poor only can experiment and more often than not, wasting both time and money.

Rich/have money = more options.
That's why rich gets richer.

Sad vicious cycle.

Oof