Column/Foundation Formwork?

Let me make sure I understand the question.  You've got to pour a concrete column.  You want to use concrete blocks as the formwork for this rather than timber, then leave the blocks in place and bury them.  Concrete blocks, that cost $1.25 each, connected together by mortar that you have to mix and apply, instead of timber, which is super cheap and can be placed using a hammer and nails...

You can use anything for formwork, as long as it can handle the pressure from the wet concrete.  If you plan to bury the blocks along with the bottom of the column, you should probably fill in all of the holes with small stone or sand, other wise the soil you bury it with will work its way into those voids and slump down at the surface.

This sounds like an expensive solution to something that already has a cheap solution.  There also could be some negatives to this that we aren't thinking of.

I suggest you hire a structural engineer, this is not something you can get from a forum like this.

Homework? you are studying structural engineering? Again, the safety of the structure and of people depends on your getting the right answer. Not something you can get on this forum.