There was some discussion on this a couple months ago:
Instead of tin-coated zinc these replacement fuses are made of pure copper or 60 copper/40 zinc alloy.
I checked my original fuses. Even though the fuse material looks dull, they aren't corroded. There was no corrosion in my fuse box. Unless you see REAL corrosion, there's no need to swap out all the fuses. That said, I did buy myself a set, since I needed replacement fuses.
It'd be interesting to compare the current protection characteristics of each type.