Id say the opposite.
Custom fences seem way worse then they actually are and train the most important skills for making pretty things those being:
1. Just using pieces and getting a feel for them
2. Dynamic Design aka if its straight 9/10 times it looks worse then a gentle curve
3. Precise building and getting a hang for the controlls
4. Creative use of Pieces
5. The fact that the front and back of a habitat are arguably more important then whats actually in it and lastly
6. Doing something yourself, no matter how small or big feels nice and is worth it
While there defenetly is skill involved, most of it is just not being afraid to try to make something even if it wont be as breathtaking as what you see a youtuber do and fences are a great small scale way to do that.
They dont have to be the most complex, literally just a mesh fence decorated with rock or wood as a base looks quite good even if its just 2 pieces, but it teaches alot about the game and i can only recommemd trying
