I get confused between heat training and straightening. What is the difference? If heat training is intentionally damaging your hair it makes no sense. I myself keep my natural hair straight 75%, but when I wash it it reverts completely. When I had heat damage it was not cute and it was obvious even when my hair was straight, it became thin. I guess it's personal but I would rather straighten my hair and be able to have it pop back to its regular condition whenever I feel instead of damaging it. If I wanted damaged hair I wouldn't have paid six fiddy.
I (personally) recommend you use heat but use it carefully as you would if you wanted your hair to revert afterwards. I can get my hair bone straight and the style will last until I shampoo it, and every single coil will pop back. You could easily enjoy the best of both worlds. If you want to heat train, you can go on you tube and see the naturals who do this for more advice because I honestly do not know much about it at all. Hope I'm being somewhat helpful