Unless it's just for looks studs that are inside a building do not need to be painted. Moistures not going to effect them.
It will have 0 effect on termites.
What was important is to build it up off the ground enough so you do not get splash back on the siding when it rains.
Any 2X pressure treated lumber is not direct ground contact rated. Needs to something like 4 X 4, 4 X 6, or 6 X 6 to be direct ground contact rated.