I used substrate heating or reptile pads on the tank bottom for years and had beautiful plants. In my 125g I have no substrate cables or pads and have, I think, beautiful plants.
If you're just heating the tank with substrate cables you can do it as well for a lot less money by using a submersible heater.
For circulation in the substrate some use RFUG filtering. RTR and daveedka are well-versed in the use of RFUG in planted tanks.
This is my first planted tank without substrate heating and I gotta say, up to this point I'm glad I saved the money.
Mark