Great question.
I consider them all to be "welfare" defined as "aid given by the government." In one case it is education, the other finances for education.
I have no moral objection to either, just practical objections.
I think that offering money for a specific use without enforcing that specific use will lead to fraud and abuse.
E.G. Food stamps. Back when it was actual stamps/coupons, people would stand outside the store in my town and offer to trade their family's food stamps for cash, cigarettes, or liquor. Now it's a debit card with restrictions, because of that abuse.
What about enforcing the specified use on individuals? It would require giving up privacy and freedom in curriculum choice.
I now have to prove to the state (or feds) that my expenses were on curriculum, I really did buy these items for school, I really did spend the required 180 days teaching, etc.
The charter schools are audited financially and academically by the state, I don't want that on an individual level.
I also would rather not have the parents who once traded their children's food stamps for cash to also trade their children's education for cash.
If there was a way to prevent the inevitable abuse at the expense of taxpayer money and worse children's education, while not infringing on my privacy and curriculum choice, I would consider a voucher for individual homeschoolers. At the federal level, I don't see any hope of this and at the state level it is unlikely.