What is the need for wp_usermeta?

Is there a need to create an additional unnecessary relation for wp_usermeta? For example, there is a 1 to 1 correlation with the IP Address a user signed up for the site with. I can’t find this variable stored anywhere, which is a major surprise. If I wanted to simply sort by IP address and easily see the users, this is not possible if you insert the IP address in the wp_usermeta and seems unnecessarily messy. After all it’s another table with its own meta key, you need to add the userid, a meta key and finally the value. All that work when you could simply store that single value in the same users table with merely one additional field. Is there a reason why this table is separated and recommended to remain “pristine?”