During my two years as totally post-pc, I haven't touched a hardware keyboard and proven that I can type really fast on touch keyboards. In fact even faster than on hardware keyboards thanks to all the extra features touch keyboards has. The auto correction and predictions is what makes it so fast typing with touch keyboards.
If you tried touchscreen typing and just didn’t get the hang of it, or if you’re simply curious, I definitely encourage you to give it a shot. Maybe give yourself some more time, or try TapTyping’s courses to train yourself in a more structured way. The mobility, weight, and freedom advantages of typing on an iPad this way have definitely been worth it for me. I’m not even considering a hardware keyboard for the iPad Pro anymore.
And yes I really enjoy the total freedom to always have a small portable device always with me everywhere, so that I can type anywhere I want. That wouldn't be possible if I needed to also have a physical hardware keyboard with me everywhere. It would be too awkward and clunky.
That's also one reason why I think the second gen 12-inch Macbook could be a great companion device to my iPhone 6s plus (and later the iPhone 7 plus). It's easier and lighter to carry than the iPad Pro with a hardware keyboard.
Via On touchscreen typing and advantages of the iPad Pro – Finer Things in Tech