These are called "wobble eels" and are made from lead free tin solder.
Advantages: No need to paint, keeps it's shiny white silver color. Tin is non-toxic to work with. It also gives a slightly different action to lures than lead because it weighs only 70 % of lead in the same size lure
Disadvantages: Costly. However from 2 lbs of solder which I purchased off a well known auction site for $8.50 per lb, I was able to produce 31 of these lures in various sizes, with some tin left over. So around 50 cents per lure in metal costs.
Last summer I caught 5 coho on a similar ("wobble fish") lure cast in tin. No diver, no other hardware....just the lure. I'm looking forward to trying these this coming season.
This is the fun side of tacklecraft...making a unique lure and then seeing if it works.