Neal told Emma that the DREAM CATCHERS involved a lot of magic and he withdrew from it … I think the only reason Neal kept the dream catcher was it reminded him of his time with Emma. I think it depends upon who is using the dream catcher and for what purpose.
You mean Rumple, was him that said to Emma that Dreamcatchers involved magic, because Neal never talked to Emma about dreamcatchers and magic, Emma was the one that explained neal what a dreamcatcher was and what was for, in this case to catch bad dreams and let the good ones in. But Neal obvious kept the dreamcatcher bc of Emma and to try not to have nightmares due to all the things that happened to him and have good ones, probably about Emma and the dreams they had.
"I offended you with my opinion? Ha, you should hear the ones I keep to myself".