It's just personal preference. Someone added a depth of field blur to my autumn pic and it looked great, and I kept it. But it's the same reason I dont like bass boosts as a musician. The mix I made is 100% mine, and I worked hard and spent a lot of time making it look the best it could. If someone comes around and asks to make changes (increase the bass) its not something I want, because people are going to come across it and hear the over-bassed mess and even though they know it's a bass boost, theyre gonna associate that with me.



I try to maintain a professional image as much as I can. As such, anything that has my name attached to it is something that will inevitably trace back to me. People coming across the image aren't going to go so deep as to understand it's an edit, and they're going to link it to me. Thats just one of the reasons I dont like derivative works.



I usually will let people use my work in their work (My art in their videos, my music in their animations) so long as they credit, but I don't allow people to make derivative work of my art/music unless I know they A) Have the skill to pull off a great work, and B) Are using my work to make other original content (remixes)



In regards to copyright, everyone owns a copyright to their original content from the moment it's first created. Even if I scribble on a livestream, others cant use my scribble without infringing copyright cause I own the copyright immediately. It doesnt need to be registered, registering a copyright just helps to prove it in court if you dont have evidence otherwise (project files and stuff)



In regards to money, it's not about money, it's just about maintaining my portfolio as an artist. I wont be doing exclusively ponies forever, eventually I'll be branching out and doing other things too. I want my history to contain my works, not derivatives.



I dont care if people use my art for references or practice (No one can stop you and no one SHOULD stop you, referenfcing and practicing using works is expected, not just permitted.) I just care if the thing is published afterwards.