You made some excellent points. I read last night that most mineral supplements cannot be absorbed and used on a cellular level. It is the tiny mitochondria, the sub cellular "energy plants" that make the body run. This same article said any mineral with the prefix "oxide" is inorganic and only a tiny percentage will be absorbed; the rest is either excreted or builds up in joints and even blood vessels. Minerals ending in citrate are absorbed a little better than oxides, but plant minerals are the best for keeping the body mineralized and healthy.
No debate here, I think you've got it absolutely right.