Practicality can be very practical. I'm less likely to buy a .280 than a .270, because the Academy in San Angelo is much more likely to stock the latter than the former. But, I'll not make, nor enforce, a "rule" against those who enjoy their .280s
As to storage of arms, as a general rull, I have the opposite stance. But, that's proabably from having met too many who balk at spending more than $500 to protect $10, 20, 30K of arms (when they will spend more on a scope, used once a year, than on their 24/7 safe). But, I may be jaded and cynical in this regard, too.
Accuracy is in the eye of the beholder. I've owned arms that shot in ragged cones, but, have been rather fun. Fun can trump group size. I had a 1903 that was a 4 MOA shooter. Just was. But, it was way more fun than an F-class that needed cleaning between every shot. Now, the Universal Carbine I owned that shot into a cone, but the cone wandered around (think 2-2.5MOA groups, but in a ragged 8-10 MOA cone) proved to just not be fun. So, it was converted into a c-note at an AstroHall gun show (many, many years ago).
So, what it comes down to, fo me (the rest of you can do your own thing) is that it needs to be fun. My military collection probably ought to have a BAR. However, BAR (even the semi versions) are just not fun to shoot. They shoot well enough, and, let's face it, a day shooting is better than a day not shooting. But, when the idea of hauling 40# of semi M1919 and a tripod is more appealing than a 19# BAR, which one to spend three grand upon?
Rules? You want to shoot a .300 magnum with a BOSS, go right ahead (I may move over a few positions, that BOSS is loud).