"Tag" vs "adding new column" dilemma

Hello Everybody,

I started to build my Calibre library a few months ago, and I keep enjoying adding books to it. However, before my library gets bigger I came to a dilemma about whether it would be better to use "Tags" or "adding new columns". I actually don't see the differences where one could be preferably used instead of the other one. Therefore, I would like to kindly ask the Calibre SMEs about their recommendations.

Thanks in advance for your time,
Peter