Regardless of the type of substrate you use and that is important-But the proper color temp lights are the driving force behind successful planted tanks-Most plant failures are due to wrong color temp lights-While we can see the light the plants can't to use it for energy/photosynthesis.
Lights that I recommend for plants-"Daylight" 6500k...watts vary based on length of bulb. Florescent light bulbs need to be changed every 12 months since the intensity can be lost over time even though they still shine-you can see it but the plants can't.
All I keep are the soil/dirt based or natural planted tanks that range from 1gal to 75gal. I use all different kinds of dirt in different tanks-Some I use either play sand, pool filter sand or small diameter gravel as the cap for the dirt/soil. The cap is to help keep the dirt/soil in place and you don't want to use a lot. I generally recommend/use half as much cap as I do base....meaning-if I use 1inch of dirt-my cap will be half inch deep.
When using dirt/soil along with proper lights-It is important to start out with enough of the right species of plants-That being-at least 3-4 different species of stem plants-enough to cover about 75% of the floor and 10-25% floating plants-like water lettuce, frogbit, duckweed and hornwort will work but it tend to get hair algae if too close to the light source or if the light are too high watts.
The soil based or natural planted tanks are great systems and once they are mature, the dirt is alive and plants thriving...It is as close to a natural ecosystem that can be created in a closed system-but its still a closed system and need some care but not like a regular substrate tanks plants or not......