Hi,
Here is what i quoted from your link :
Discus can grow in planted tank with less water changes. But the growth rate wont be as fast or as good as in bare bottom tank with a frequent water changes. I used to keep my discus in planted tank. All my tanks are bare bottom now. It is much easier to clean the bare bottom tanks, easier to maintain a good quality water.I am certainly no beginner, having kept fish for over 30 years, owned both retail stores and a wholesaler distributorship, and I currently breed Angels commercially
Bare bottom is a better way for beginner, IMO.
HTH,
Ronny