i cant argue for or against a buttonless keyboard as ive only used the ones with physical buttons.
However we should keep in mind that the arguments for physical keys have good reason and are rooted deep in tech history. Remember students of a typing class on older typewriters used to get scolded for looking down at the keyboard when typing. Finger placement, hand positioning, and being able to feel your way around a keyboard is still considered to be essential to efficient input on such devices.
So we should easily see why not being able to touch and feel the individual keys might make a lot of people question the efficiency and practicality of a buttonless keyboard.
Now create a small portable keyboard so that you cant lay all 10 fingers down. One that its meant to be poked around with thumbs or index fingers only. So that the range and number of keys those fingers have to touch are increased substantially. And take away the buttons so its a flat surface with only visual feedback. Like i said. I can't say its impractical because i havent used it but I could see why there is concern.
Also I'm no beethoven but I do play piano and other musical instruments as a hobby. I can tell you that even in those areas tactile feedback (the word you seem to dislike) is extremely important to musicians who value the quality of instruments. Each key you press or plug (strings) has it's unique and valuable resistance, throw (momentum), and recoil speed. All factors that have an impact on how the musician sounds when playing the instrument.
Keyboards are not very different than musical instruments. I know hard core gamers that swear and stick to only the finest gaming input devices for the very reason of tactile feedback.