I assume that why is why am I considering it...
There are a few factors.
First, I absolutely wouldn't be considering a 3-5 round fixed mag bolt action rifle. That would be too limiting, and unlike a lever gun with a loading gate, very slow to reload individual rounds. The guns I'm considering all have removable mags, and a minimum capacity of 10 rounds (the two that take AR rounds can go to about 20 round mags and still work reliably).
Many people (myself included) consider pistol caliber lever rifles to be suitable as a home defense carbine. The round count on these particular bolt rifles will be the same or better with much quicker reloads.
Second, I live in MD which is very anti-gun. States Attorneys in some parts of the state have been known to charge people regardless of the facts after a self defense shoot and let the jury decide it. Even those areas where it isn't quite automatic, many parts of the state, the county prosecutors will be looking for any excuse. So, I want as PC looking a home defense gun as possible so the prosecutor won't think I'm a Rambo want-to-be that he/she has to charge, and if charged, a jury that hates or does't know guns won't see an "evil black rifle." The more it looks like grampa's hunting rifle, the better (I
really need to retire my AR from potential home defense duties).
Bolt actions have some benefits. They are highly reliable. Two of the bolt rifles I'm considering are significantly cheaper than the M1 Carbine and Mini 14 that make up my top two choices, or the further down the list lever rifles. Both bolts actions and lever actions can be pretty quick to operate with practice, they aren't as slow as many people envision (or don't have to be). I'm not spray and praying, especially for home defense I will be taking a moment for aimed shots as much as I can.
In general, I think these 10 (or greater) round removable box magazine, short and light, bolt action rifles with iron sights or the right optic can make a good home defense gun. For someone in the right circumstances (live in an anti-gun state and want to improve your post-shoot chances, you are a hunter with a lot of bolt action experience, you seriously want something different) these can be more than adequate and can be quite a good choice for many people. I wouldn't say that as a blanket statement about all bolt rifles, but about the scout and similar lightweight rifles in the right calibers (mainly .223/5.56), they can work well.
Yes, a semi-auto is still my first choice right now. My emotional first choice based mainly on want and not how many boxes it checks would go to a Winchester 92, Uberti Win 1866 reproduction, or a Henry Big Boy. However, I am seriously considering those few bolt action rifles that look like they'd make good home defense rifles. Partly to do something different, but largely to get something as PC looking as possible yet still quite capable as a home defense gun.