Never pass up soft lead.
Pure lead can be alloyed to whatever hardness you want, if need be.
But hard alloys such as wheelweights will always be hard and there's some applications where it's too hard (ie: patched round balls for rifles).
I keep a lot of WW ingots for cannonballs, but I always keed a small stock of pure lead for rifle balls and it's always more difficult (and more expensive) to get the soft lead when I need it.
Soft lead is generally worth more than wheelweights, so if nothing else it's good trading stock.