Some of my tanks have them, some not. Depends on what substrate you're using - I wouldn't fancy using a soily/peat containing substrate like Dennerle's without a cable. The other consideration is the temperature of the room and the insulation at the bottom of the tank - I've had tanks in cold rooms that had noticably cold substrates (I could tell when I was replanting). I'm sure that can't be optimal for growth - soil heaters have been used in terrestrial horticulture for over 200 years, and I wouldn't want my plants to be growing in two widely differing temperature zones.
If you have a modern house with double glazing, insulation, and heating this won't be a problem.
I had a small tank years ago that wasn't really being used so I set it up with soil/sand under gravel with a cable, tiny internal filter and (I think) just one tube for light. No CO2 or fertilisers. It grew like a mental thing, even plants that were supposed to be small had to be harvested weekly, and in the end I took it down cos it was so much work keeping up with the plant growth, and just put a fighter in it.
I wouldn't be worried about setting up a tank without a cable, but I don't understand the current 'hatred' of using them. Just a fashion I suppose - maybe next year Amano will start using large swordplants in his tanks again, and then the current batch of Cyperus, Pogostemon and Utricularia will all be composted and everyone will have to have the latest sword! (Actually it's more likely that he'll start using a plant we haven't heard of yet, or that hasn't been used for 50 years.) There are lots of fantastic tanks on this site (and others), but they are so fashion led - looking at any picture of a planted aquarium from the last fifteen years it's quite easy to date it to within a year or two - what about Amano's turquoise background years (thank god that never took off in a big way!).
There's plenty of options available in equipping, designing, planting and maintaining a tank, and I'm for it. Choice, freedom, creativity, patience, nurturing.
Enjoy all your tanks, and enjoy other people's - even if they have some different ideas from you! Nick the ideas you like, ignore the others!
Mark