The Green Table is very similar to The Red Shelf in its functionality. You use the table to free-place chairs. Say you want a chair to not slot to a table nearby, you can slot it to The Green Table, and then avoid slotting. Or if you want a chair pulled out at your dining table, you can slot it to The Green Table, and then place the chair without struggle.
Note: The table will not work with the gallery. As in, if someone downloads your lot/room and doesn't have the green table installed, it won't work. So this would be better for strictly personal builds.
Note #2: There are 2 files, one with slots, and one without slots. You cannot have both in your game at once, or else they will override each other.