Hello mate.

Support and resistance shows us an area where price has tested a few times and failed to break through.

Supply and demand goes a bit deeper. S/D shows us an area where buyers and sellers are met at a sort of equilibrium and then due to an imbalance in the order books, we see a huge reaction one way or the other. If we rally, can get a good idea that there isn't much selling pressure at that level, and vice versa. S/R can't offer the same sort of depth of insight.

With S/D we look for areas of strong price movement which usually react in the same direction when price revisits