This is the best metric for the regular users who are having the availability to them for determining the valued member of the site. If someone is having more karma wither the link or the comments that it means that the user have contributed very popular content to the site. You can note that the content might not be the good content but it was upvoted.
There is the requirement to meet the minimum karma score for the post on certain subreddits such as r/videos, which requires 10 link and the comment karma. This was done in the effort to combating the spam from the newly created accounts.
It is also required to meet the minimum karma score before being allowed to join the few private subreddits such as r/centuryclub.
Karma is having no value outside of reddit and inside reddit it is most valuable and useful to the user but it is having the occasional uses.
Reddit is the best forum websites and karma is one of the gamification technique used for engaging the users on reddit. It is pretty similar to Quora credits. You will get more karma when the posts and comments will get upvoted and you will lose some when it is downvoted.
There are various benefits of having the reddit karma such as the mod of the popular sub reddit. There is the high chance when your account will not get suspended and when you are doing the self-promotion. You will also be able to sell your account for money. Karma is not needed anymore for browsing the reddit but if you posting on the sub reddit then you should get some of the powerful karma. You can also get to buy upvotes when you are checking it.
The karma of reddit is the gamification techniques which is used for engaging the users on reddit. It is very similar to the credits of quora. You will get more karma when you are posting and commenting and getting upvoted. There are two main differences which you can think of it:
Reddit karma cannot be redeemed for anything even on the website. The credits of quora can be used for asking questions for A2A and for promoting the content. There are number of users whose credits are accumulated.
The karma of reddit are displayed publicly. This also means that everyone who want to know can see how much the karma is accumulated.