yes, warm & natural is a needle punched batting- needle punched batting is a batting that has the 'batting fibers' punched through a scrim * a net like stabilizer* creating a more stable batting that allows quilting stitches to be further apart (warm & natural allows up to 10" between quilting lines- instead of the 2"- 4" that is normal)
as for quilting without backing- yes, you can do it- how ever- it is more difficult- the batting does not move as smoothly as cotton fabric- also, at some point you need to add a backing- to protect the batting fibers-which will wear away with use/friction and you would not be able to launder/clean the item without backing enclosing the batting.