Gaming on prebuilts is possible, its just expensive. Some people are willing to pay a premium for things like portability or touch screens.
Stop blindly recommending custom computers like mindless drones.
laptops aren't the same as AIO system (or atleast laptops can be used on the move, AIO systems cannot)
by saying similar you mean having a desktop with laptop parts? (which to me makes no sense, just like imacs)
gaming on an AIO is like trying to win a 100m sprint by having 1 leg tied up... (it is possible ,yet makes no sense)
last time i checked AIO systems were also intended for average multimedia use at best.
lets not mix up two things that are alike but still got quite some significant advantages/disadvantages to either side.
So we must force everyone to buy the most cost effective computer and ridicule the OP for not doing so.
Yes, we must reach our hand through our monitors, past a vast expanse of the world and shake him by his collar saying "YOU BUY WHAT'S BEST FOR YOU, OR ELSE!"
No one's doing anything but recommending the best method to get what his friend wants. If his friend still wants to waste his money on a touchscreen AIO that would make even a budget desktop or mid-range laptop giggle that's his prerogative. But that's not going to stop anyone from at least attempting to urge him towards a better option for his purposes.