Capcom, Nintendo, SNK, Type-Moon, etc. all do this, even for pictures of single characters by artists unaffiliated with the series parent company. Of those examples I'd say only Type-Moon is the only one that's kinda justified.
Besides the aforementioned crossover and official art images, I simply don't see the need.
Not to mention it also gives undue preference to gaming companies. For example, we certainly don't give anime studios the same consideration.
One of the old arguments I saw in one or two of those threads is that it allows the user to see all that a company has made with a click, which is simply a trite, silly reason for keeping this in practice. You think I wouldn't like to click Kyoto Animation or something and have it return every series and character? Well, tough. I deal with it.
Plus I thought we didn't use tags to shorten tag combinations and such unless it's actually needed and not just to appease laziness.