Of course you have to have the proper gas to clutch ratio, Unless you mean just never using the brake. If it's steep enough, your foot still has to move from the brake to the gas. If the hill is steep, and the person behind you is riding your ass, you may very well roll back enough to hit them in the time it takes to move your foot from brake to gas. Which is why you'd need to use the hand brake to give yourself the time to move your foot to gas, then get the right ratio, and release the hand brake.
SugarSnack mentioned something different. This is not applicable to all cars. Plenty of cars would stall out before getting enough forward momentum to beat gravity, without a push from the gas. Of course if your clutch acts as clutch AND gas, then you can do this no problem.
There is a bite point where you don't need to use the brake at all, just clutch and accelerator in perfect harmony. With practice you'll be able to stay perfectly still, or inch forwards or backwards even on steep hills.
It does get tiring if you have to hold it too long though.
I could see this being possible, but it seems like mlg meant something different. They were talking about letting off the clutch before taking your foot off the brake. Your solution seems applicable in more cars, but not universally applicable in any situation. I could definitely see this being a pain for a long light, though.
He must drive a pickup. With their deep gearing, yeah I do this all the time, no problem, no excessive clutch wear. Modern car on a steep hill, highway gearing, smaller motor tuned for higher rpm hp not lower end torque, yeah I start handbrake launching on steep hills, or heel toeing the gas n brake.
You hold the clutch at the bite point before you even reach the gas.
He says before you even reach the gas, which means you are moving your foot from brake to gas.
In the UK you do hill starts as a part of the driving test. They're not useless because if you don't know how to do it, then you're going to roll back or cut out when you start off and that's a fail. Plenty of places have roads and hills. Hence why they're part of the test. Typically, you apply the parking brake, release the clutch enough to "bite" and hold you in place, release the brake and continue to release the clutch as you press on the accelerator. All in a controlled fashion.
Of course, fancier cars have hill start assist and electronic parking brakes these days so I don't know what happens if you show up for your test in one of those - they probably just do the test anyway because I'm sure people still manage to screw up.