But this is where you are overlooking stats that show Hand is much, much better than Neris. Some of those losses and blown saves might not have been his fault. Neris, on the other hand, has been bad because he has been very hittable. Hand has also given up 6 unearned runs which means some of the losses or blown saves might have been the fault of others.
Hand vs Neris:
ERA: 2.82 vs 5.79
Whip 1.017 vs 1.464
H/9: 5.6 vs 10.0
K/9: 13.1 vs 11.9
FIP 3.52 vs 5.36
HR/9: 1.2 vs 2.6
Neris has been legitimately bad because he has been very hittable. Hand has not been great, but he has been very solid and the H/9 and K/9 suggest he has been a little unlucky (as the unearned runs do as well). Hand's stuff (like his velocity) are also trending up. The reasons he is valuable are largely stuff-based (plus what is seen as a favorable contract for three years).
Plus we really need a quality LHP.