that is a limitation of your memory, not the technique. I have never forgot to focus, just like I never forgot to press the shutter button, or zoomed out, or composed. Just because you kept forgetting to focus doesn't mean the method has a limitation, you can't blame the method for you inability to remember to do something.
It doesn't have any limitations. The one you pointed out is not a limitation of the method, just one of your memory.
There is no thumb movement. My thumb is always resting on the button. It takes no longer, it happens at the exact same time.
Once again, you may have found it easy to forget, but that's because you don't use the technique all the time. That's just your memory. Once it's instinctive, you never forget, you don't even think about it, just like you don't think about pressing the shutter, it just happens at the same time
No one is trying to convert you, if anything it comes across like you are trying to justify your reasons for not using bbf. There's nothing wrong with shutter focussing, no inadequacy or anything, choose the method that suits you best.
The fact is, there is no limitation to bbf though, doesn't mean it's the right method for you, we are all different and prefer different things. That's our prerogative.