I think the problem with karma/reputation systems is that the source of karma are fungible - anyone's upvote has the same effect on the reputation. And this makes it gameable.
A personalized system can solve this by replacing global reputation with user-to-user trust. Now it matters who upvoted - a random bot or a user whose past contributions have been useful to you.
In that system how do you create a ranked list of content for a user to browse? Isn't it going to be very heavy on processing demand?
This is more computationally intensive than sorting by the raw number of upvotes or weight upvotes by karma/popularity.
But I think this is a useful computation - the user can be more confident that the content they is is not astroturfed and comes from trustworthy users.
Details of how trust is calculated: https://linklonk.com/item/3292763817660940288