Is saving disk space still considered an advantage of normalization?
Normalization was never about saving disk space. In his 1971 normalization paper E.F.Codd wrote: "It is important to remember that we are not making a case for or against any physical storage structures in this paper"[1] (emphasis in the original).

Normalization is all about the best logical representation for data and by no means implies that a normalized database will take up less space than a denormalized one.

Given the range of advances in database storage techniques since then (e.g. compressed formats, join indexes, columnar storage) there is probably even less correlation between normalization and storage size today than there was 50 years ago.



[1] Normalized Data Base Structure: A Brief Tutorial