I’ve got disc brakes on my road bike with full mudguards and a rack and it makes it sssooo much better for year round commuting. When its raining really hard, rim brakes just don’t work. If someone pulls out on you, you’re stuffed. it doesn’t matter how carefully you ride, unexpected stuff can always happen.
A road bike tyre has more grip than a mtb tyre in many situations too, locking up wheels just doesn’t happen (unless you want it to).
having said all this, my road bike would probably be considered a “tourer” but i can’t be bothered trying to work out what niche its in.
If its got drops and slicks its a road bike!