People trade magic for several reasona.
Everyone has their own opinions and thoughts on topics like these.
This is just mine :
Some people could be trading cause theyre one of the greedy people who do not respect the art of magic, want to learn all the magic tricks they could, not perfect them, and perform them for whatever reason (fame, girls, idk)
Some people could be trading because of their lack of funds for magic.
These (some) people could be the same people as the ones above, or serious magicians who want to perfect their art.
BASICALLY, it really depends on the situation like everything else in life...
there could be hundereds of answers for threads like these
MY opinions : well, i trade. i dont believe its wrong, as long as its someone your close to who also respects magic as much as you do. but to the people who are on youtube begging for tricks...well, they can do whatever they want, becuase we really cant do much about them.