First off, smithing is pretty much only popular to lower levels and F2P players. Why? The prospect of being able to create your own armor entices low level players. Naturally, they have no knowledge of efficient money making antics and play the game simply for FUN. Higher levels play the game to get experience, and thus indulge in other skills. The variety of skills offered to F2P members is also very limited, ranging from fighting skills, to smithing oriented skills, to crafting and woodcutting oriented skills. The first thing someone does after they have gained an understanding of their surroundings in an MMORPG is they try to improve their stats or gain money. There are pretty much only two options given to low level players to obtain GP: mining and fishing. Fishing is hardly profitable at low levels, as nobody buys salmon or tuna. On the other hand, iron and coal ores can rake in a reasonable profit. Newbies grasp this opportunity to gain some wealth and in the process find themselves wanting to smith the ores they have acquired. Overall, noobs just smith because it's the easiest/most fun thing to do for them.