A Bond is bought with a lump sum. It is an investment not insurance. There is no fixed term.
The money is invested in an investment fund.
A standard bond will not have any special tax concessions for being used to pay long term care .The benefits may be taxable.
The investment value can go up as well as down.
Some Long Term Care Bonds are designed so that any investment income and/or increase in value of the investment can be used to fund care.
The real risk is that at the time you need care, there is a dip in the value of the funds, so there is little or even no money to pay for care.
Several insurers used to offer this product, but withdrew.
So far, we have not found any current companies offering this type of bond.