PDF is simply the lowest common denominator of what counts as "computerized sheaf of paper, with a layout and appearance that won't shift over time, no matter w

PDF is simply the lowest common denominator of what counts as "computerized sheaf of paper, with a layout and appearance that won't shift over time, no matter which reader software you use". It has its value, especially with preservation of pre-digital documents. Accepting a potentially inferior machine-readable plaintext when copy and pasting is the price we pay for having something like that available.